text: ( function () {
  
  	class GLTFLoader extends THREE.Loader {
  
  		constructor( manager ) {
  
  			super( manager );
  			this.dracoLoader = null;
  			this.ktx2Loader = null;
  			this.meshoptDecoder = null;
  			this.pluginCallbacks = [];
  			this.register( function ( parser ) {
  
  				return new GLTFMaterialsClearcoatExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFTextureBasisUExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFTextureWebPExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFMaterialsSheenExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFMaterialsTransmissionExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFMaterialsVolumeExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFMaterialsIorExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFMaterialsSpecularExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFLightsExtension( parser );
  
  			} );
  			this.register( function ( parser ) {
  
  				return new GLTFMeshoptCompression( parser );
  
  			} );
  
  		}
  
  		load( url, onLoad, onProgress, onError ) {
  
  			const scope = this;
  			let resourcePath;
  
  			if ( this.resourcePath !== '' ) {
  
  				resourcePath = this.resourcePath;
  
  			} else if ( this.path !== '' ) {
  
  				resourcePath = this.path;
  
  			} else {
  
  				resourcePath = THREE.LoaderUtils.extractUrlBase( url );
  
  			} // Tells the LoadingManager to track an extra item, which resolves after
  			// the model is fully loaded. This means the count of items loaded will
  			// be incorrect, but ensures manager.onLoad() does not fire early.
  
  
  			this.manager.itemStart( url );
  
  			const _onError = function ( e ) {
  
  				if ( onError ) {
  
  					onError( e );
  
  				} else {
  
  					console.error( e );
  
  				}
  
  				scope.manager.itemError( url );
  				scope.manager.itemEnd( url );
  
  			};
  
  			const loader = new THREE.FileLoader( this.manager );
  			loader.setPath( this.path );
  			loader.setResponseType( 'arraybuffer' );
  			loader.setRequestHeader( this.requestHeader );
  			loader.setWithCredentials( this.withCredentials );
  			loader.load( url, function ( data ) {
  
  				try {
  
  					scope.parse( data, resourcePath, function ( gltf ) {
  
  						onLoad( gltf );
  						scope.manager.itemEnd( url );
  
  					}, _onError );
  
  				} catch ( e ) {
  
  					_onError( e );
  
  				}
  
  			}, onProgress, _onError );
  
  		}
  
  		setDRACOLoader( dracoLoader ) {
  
  			this.dracoLoader = dracoLoader;
  			return this;
  
  		}
  
  		setDDSLoader() {
  
  			throw new Error( 'THREE.GLTFLoader: "MSFT_texture_dds" no longer supported. Please update to "KHR_texture_basisu".' );
  
  		}
  
  		setKTX2Loader( ktx2Loader ) {
  
  			this.ktx2Loader = ktx2Loader;
  			return this;
  
  		}
  
  		setMeshoptDecoder( meshoptDecoder ) {
  
  			this.meshoptDecoder = meshoptDecoder;
  			return this;
  
  		}
  
  		register( callback ) {
  
  			if ( this.pluginCallbacks.indexOf( callback ) === - 1 ) {
  
  				this.pluginCallbacks.push( callback );
  
  			}
  
  			return this;
  
  		}
  
  		unregister( callback ) {
  
  			if ( this.pluginCallbacks.indexOf( callback ) !== - 1 ) {
  
  				this.pluginCallbacks.splice( this.pluginCallbacks.indexOf( callback ), 1 );
  
  			}
  
  			return this;
  
  		}
  
  		parse( data, path, onLoad, onError ) {
  
  			let content;
  			const extensions = {};
  			const plugins = {};
  
  			if ( typeof data === 'string' ) {
  
  				content = data;
  
  			} else {
  
  				const magic = THREE.LoaderUtils.decodeText( new Uint8Array( data, 0, 4 ) );
  
  				if ( magic === BINARY_EXTENSION_HEADER_MAGIC ) {
  
  					try {
  
  						extensions[ EXTENSIONS.KHR_BINARY_GLTF ] = new GLTFBinaryExtension( data );
  
  					} catch ( error ) {
  
  						if ( onError ) onError( error );
  						return;
  
  					}
  
  					content = extensions[ EXTENSIONS.KHR_BINARY_GLTF ].content;
  
  				} else {
  
  					content = THREE.LoaderUtils.decodeText( new Uint8Array( data ) );
  
  				}
  
  			}
  
  			const json = JSON.parse( content );
  
  			if ( json.asset === undefined || json.asset.version[ 0 ] < 2 ) {
  
  				if ( onError ) onError( new Error( 'THREE.GLTFLoader: Unsupported asset. glTF versions >=2.0 are supported.' ) );
  				return;
  
  			}
  
  			const parser = new GLTFParser( json, {
  				path: path || this.resourcePath || '',
  				crossOrigin: this.crossOrigin,
  				requestHeader: this.requestHeader,
  				manager: this.manager,
  				ktx2Loader: this.ktx2Loader,
  				meshoptDecoder: this.meshoptDecoder
  			} );
  			parser.fileLoader.setRequestHeader( this.requestHeader );
  
  			for ( let i = 0; i < this.pluginCallbacks.length; i ++ ) {
  
  				const plugin = this.pluginCallbacks[ i ]( parser );
  				plugins[ plugin.name ] = plugin; // Workaround to avoid determining as unknown extension
  				// in addUnknownExtensionsToUserData().
  				// Remove this workaround if we move all the existing
  				// extension handlers to plugin system
  
  				extensions[ plugin.name ] = true;
  
  			}
  
  			if ( json.extensionsUsed ) {
  
  				for ( let i = 0; i < json.extensionsUsed.length; ++ i ) {
  
  					const extensionName = json.extensionsUsed[ i ];
  					const extensionsRequired = json.extensionsRequired || [];
  
  					switch ( extensionName ) {
  
  						case EXTENSIONS.KHR_MATERIALS_UNLIT:
  							extensions[ extensionName ] = new GLTFMaterialsUnlitExtension();
  							break;
  
  						case EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS:
  							extensions[ extensionName ] = new GLTFMaterialsPbrSpecularGlossinessExtension();
  							break;
  
  						case EXTENSIONS.KHR_DRACO_MESH_COMPRESSION:
  							extensions[ extensionName ] = new GLTFDracoMeshCompressionExtension( json, this.dracoLoader );
  							break;
  
  						case EXTENSIONS.KHR_TEXTURE_TRANSFORM:
  							extensions[ extensionName ] = new GLTFTextureTransformExtension();
  							break;
  
  						case EXTENSIONS.KHR_MESH_QUANTIZATION:
  							extensions[ extensionName ] = new GLTFMeshQuantizationExtension();
  							break;
  
  						default:
  							if ( extensionsRequired.indexOf( extensionName ) >= 0 && plugins[ extensionName ] === undefined ) {
  
  								console.warn( 'THREE.GLTFLoader: Unknown extension "' + extensionName + '".' );
  
  							}
  
  					}
  
  				}
  
  			}
  
  			parser.setExtensions( extensions );
  			parser.setPlugins( plugins );
  			parser.parse( onLoad, onError );
  
  		}
  
  		parseAsync( data, path ) {
  
  			const scope = this;
  			return new Promise( function ( resolve, reject ) {
  
  				scope.parse( data, path, resolve, reject );
  
  			} );
  
  		}
  
  	}
  	/* GLTFREGISTRY */
  
  
  	function GLTFRegistry() {
  
  		let objects = {};
  		return {
  			get: function ( key ) {
  
  				return objects[ key ];
  
  			},
  			add: function ( key, object ) {
  
  				objects[ key ] = object;
  
  			},
  			remove: function ( key ) {
  
  				delete objects[ key ];
  
  			},
  			removeAll: function () {
  
  				objects = {};
  
  			}
  		};
  
  	}
  	/*********************************/
  
  	/********** EXTENSIONS ***********/
  
  	/*********************************/
  
  
  	const EXTENSIONS = {
  		KHR_BINARY_GLTF: 'KHR_binary_glTF',
  		KHR_DRACO_MESH_COMPRESSION: 'KHR_draco_mesh_compression',
  		KHR_LIGHTS_PUNCTUAL: 'KHR_lights_punctual',
  		KHR_MATERIALS_CLEARCOAT: 'KHR_materials_clearcoat',
  		KHR_MATERIALS_IOR: 'KHR_materials_ior',
  		KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness',
  		KHR_MATERIALS_SHEEN: 'KHR_materials_sheen',
  		KHR_MATERIALS_SPECULAR: 'KHR_materials_specular',
  		KHR_MATERIALS_TRANSMISSION: 'KHR_materials_transmission',
  		KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
  		KHR_MATERIALS_VOLUME: 'KHR_materials_volume',
  		KHR_TEXTURE_BASISU: 'KHR_texture_basisu',
  		KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
  		KHR_MESH_QUANTIZATION: 'KHR_mesh_quantization',
  		EXT_TEXTURE_WEBP: 'EXT_texture_webp',
  		EXT_MESHOPT_COMPRESSION: 'EXT_meshopt_compression'
  	};
  	/**
   * Punctual Lights Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual
   */
  
  	class GLTFLightsExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.KHR_LIGHTS_PUNCTUAL; // THREE.Object3D instance caches
  
  			this.cache = {
  				refs: {},
  				uses: {}
  			};
  
  		}
  
  		_markDefs() {
  
  			const parser = this.parser;
  			const nodeDefs = this.parser.json.nodes || [];
  
  			for ( let nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex ++ ) {
  
  				const nodeDef = nodeDefs[ nodeIndex ];
  
  				if ( nodeDef.extensions && nodeDef.extensions[ this.name ] && nodeDef.extensions[ this.name ].light !== undefined ) {
  
  					parser._addNodeRef( this.cache, nodeDef.extensions[ this.name ].light );
  
  				}
  
  			}
  
  		}
  
  		_loadLight( lightIndex ) {
  
  			const parser = this.parser;
  			const cacheKey = 'light:' + lightIndex;
  			let dependency = parser.cache.get( cacheKey );
  			if ( dependency ) return dependency;
  			const json = parser.json;
  			const extensions = json.extensions && json.extensions[ this.name ] || {};
  			const lightDefs = extensions.lights || [];
  			const lightDef = lightDefs[ lightIndex ];
  			let lightNode;
  			const color = new THREE.Color( 0xffffff );
  			if ( lightDef.color !== undefined ) color.fromArray( lightDef.color );
  			const range = lightDef.range !== undefined ? lightDef.range : 0;
  
  			switch ( lightDef.type ) {
  
  				case 'directional':
  					lightNode = new THREE.DirectionalLight( color );
  					lightNode.target.position.set( 0, 0, - 1 );
  					lightNode.add( lightNode.target );
  					break;
  
  				case 'point':
  					lightNode = new THREE.PointLight( color );
  					lightNode.distance = range;
  					break;
  
  				case 'spot':
  					lightNode = new THREE.SpotLight( color );
  					lightNode.distance = range; // Handle spotlight properties.
  
  					lightDef.spot = lightDef.spot || {};
  					lightDef.spot.innerConeAngle = lightDef.spot.innerConeAngle !== undefined ? lightDef.spot.innerConeAngle : 0;
  					lightDef.spot.outerConeAngle = lightDef.spot.outerConeAngle !== undefined ? lightDef.spot.outerConeAngle : Math.PI / 4.0;
  					lightNode.angle = lightDef.spot.outerConeAngle;
  					lightNode.penumbra = 1.0 - lightDef.spot.innerConeAngle / lightDef.spot.outerConeAngle;
  					lightNode.target.position.set( 0, 0, - 1 );
  					lightNode.add( lightNode.target );
  					break;
  
  				default:
  					throw new Error( 'THREE.GLTFLoader: Unexpected light type: ' + lightDef.type );
  
  			} // Some lights (e.g. spot) default to a position other than the origin. Reset the position
  			// here, because node-level parsing will only override position if explicitly specified.
  
  
  			lightNode.position.set( 0, 0, 0 );
  			lightNode.decay = 2;
  			if ( lightDef.intensity !== undefined ) lightNode.intensity = lightDef.intensity;
  			lightNode.name = parser.createUniqueName( lightDef.name || 'light_' + lightIndex );
  			dependency = Promise.resolve( lightNode );
  			parser.cache.add( cacheKey, dependency );
  			return dependency;
  
  		}
  
  		createNodeAttachment( nodeIndex ) {
  
  			const self = this;
  			const parser = this.parser;
  			const json = parser.json;
  			const nodeDef = json.nodes[ nodeIndex ];
  			const lightDef = nodeDef.extensions && nodeDef.extensions[ this.name ] || {};
  			const lightIndex = lightDef.light;
  			if ( lightIndex === undefined ) return null;
  			return this._loadLight( lightIndex ).then( function ( light ) {
  
  				return parser._getNodeRef( self.cache, lightIndex, light );
  
  			} );
  
  		}
  
  	}
  	/**
   * Unlit Materials Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_unlit
   */
  
  
  	class GLTFMaterialsUnlitExtension {
  
  		constructor() {
  
  			this.name = EXTENSIONS.KHR_MATERIALS_UNLIT;
  
  		}
  
  		getMaterialType() {
  
  			return THREE.MeshBasicMaterial;
  
  		}
  
  		extendParams( materialParams, materialDef, parser ) {
  
  			const pending = [];
  			materialParams.color = new THREE.Color( 1.0, 1.0, 1.0 );
  			materialParams.opacity = 1.0;
  			const metallicRoughness = materialDef.pbrMetallicRoughness;
  
  			if ( metallicRoughness ) {
  
  				if ( Array.isArray( metallicRoughness.baseColorFactor ) ) {
  
  					const array = metallicRoughness.baseColorFactor;
  					materialParams.color.fromArray( array );
  					materialParams.opacity = array[ 3 ];
  
  				}
  
  				if ( metallicRoughness.baseColorTexture !== undefined ) {
  
  					pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture, THREE.sRGBEncoding ) );
  
  				}
  
  			}
  
  			return Promise.all( pending );
  
  		}
  
  	}
  	/**
   * Clearcoat Materials Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_clearcoat
   */
  
  
  	class GLTFMaterialsClearcoatExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.KHR_MATERIALS_CLEARCOAT;
  
  		}
  
  		getMaterialType( materialIndex ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
  			return THREE.MeshPhysicalMaterial;
  
  		}
  
  		extendMaterialParams( materialIndex, materialParams ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
  
  				return Promise.resolve();
  
  			}
  
  			const pending = [];
  			const extension = materialDef.extensions[ this.name ];
  
  			if ( extension.clearcoatFactor !== undefined ) {
  
  				materialParams.clearcoat = extension.clearcoatFactor;
  
  			}
  
  			if ( extension.clearcoatTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'clearcoatMap', extension.clearcoatTexture ) );
  
  			}
  
  			if ( extension.clearcoatRoughnessFactor !== undefined ) {
  
  				materialParams.clearcoatRoughness = extension.clearcoatRoughnessFactor;
  
  			}
  
  			if ( extension.clearcoatRoughnessTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'clearcoatRoughnessMap', extension.clearcoatRoughnessTexture ) );
  
  			}
  
  			if ( extension.clearcoatNormalTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'clearcoatNormalMap', extension.clearcoatNormalTexture ) );
  
  				if ( extension.clearcoatNormalTexture.scale !== undefined ) {
  
  					const scale = extension.clearcoatNormalTexture.scale;
  					materialParams.clearcoatNormalScale = new THREE.Vector2( scale, scale );
  
  				}
  
  			}
  
  			return Promise.all( pending );
  
  		}
  
  	}
  	/**
   * Sheen Materials Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_sheen
   */
  
  
  	class GLTFMaterialsSheenExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.KHR_MATERIALS_SHEEN;
  
  		}
  
  		getMaterialType( materialIndex ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
  			return THREE.MeshPhysicalMaterial;
  
  		}
  
  		extendMaterialParams( materialIndex, materialParams ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
  
  				return Promise.resolve();
  
  			}
  
  			const pending = [];
  			materialParams.sheenColor = new THREE.Color( 0, 0, 0 );
  			materialParams.sheenRoughness = 0;
  			materialParams.sheen = 1;
  			const extension = materialDef.extensions[ this.name ];
  
  			if ( extension.sheenColorFactor !== undefined ) {
  
  				materialParams.sheenColor.fromArray( extension.sheenColorFactor );
  
  			}
  
  			if ( extension.sheenRoughnessFactor !== undefined ) {
  
  				materialParams.sheenRoughness = extension.sheenRoughnessFactor;
  
  			}
  
  			if ( extension.sheenColorTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'sheenColorMap', extension.sheenColorTexture, THREE.sRGBEncoding ) );
  
  			}
  
  			if ( extension.sheenRoughnessTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'sheenRoughnessMap', extension.sheenRoughnessTexture ) );
  
  			}
  
  			return Promise.all( pending );
  
  		}
  
  	}
  	/**
   * Transmission Materials Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_transmission
   * Draft: https://github.com/KhronosGroup/glTF/pull/1698
   */
  
  
  	class GLTFMaterialsTransmissionExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.KHR_MATERIALS_TRANSMISSION;
  
  		}
  
  		getMaterialType( materialIndex ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
  			return THREE.MeshPhysicalMaterial;
  
  		}
  
  		extendMaterialParams( materialIndex, materialParams ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
  
  				return Promise.resolve();
  
  			}
  
  			const pending = [];
  			const extension = materialDef.extensions[ this.name ];
  
  			if ( extension.transmissionFactor !== undefined ) {
  
  				materialParams.transmission = extension.transmissionFactor;
  
  			}
  
  			if ( extension.transmissionTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'transmissionMap', extension.transmissionTexture ) );
  
  			}
  
  			return Promise.all( pending );
  
  		}
  
  	}
  	/**
   * Materials Volume Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_volume
   */
  
  
  	class GLTFMaterialsVolumeExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.KHR_MATERIALS_VOLUME;
  
  		}
  
  		getMaterialType( materialIndex ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
  			return THREE.MeshPhysicalMaterial;
  
  		}
  
  		extendMaterialParams( materialIndex, materialParams ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
  
  				return Promise.resolve();
  
  			}
  
  			const pending = [];
  			const extension = materialDef.extensions[ this.name ];
  			materialParams.thickness = extension.thicknessFactor !== undefined ? extension.thicknessFactor : 0;
  
  			if ( extension.thicknessTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'thicknessMap', extension.thicknessTexture ) );
  
  			}
  
  			materialParams.attenuationDistance = extension.attenuationDistance || 0;
  			const colorArray = extension.attenuationColor || [ 1, 1, 1 ];
  			materialParams.attenuationColor = new THREE.Color( colorArray[ 0 ], colorArray[ 1 ], colorArray[ 2 ] );
  			return Promise.all( pending );
  
  		}
  
  	}
  	/**
   * Materials ior Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_ior
   */
  
  
  	class GLTFMaterialsIorExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.KHR_MATERIALS_IOR;
  
  		}
  
  		getMaterialType( materialIndex ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
  			return THREE.MeshPhysicalMaterial;
  
  		}
  
  		extendMaterialParams( materialIndex, materialParams ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
  
  				return Promise.resolve();
  
  			}
  
  			const extension = materialDef.extensions[ this.name ];
  			materialParams.ior = extension.ior !== undefined ? extension.ior : 1.5;
  			return Promise.resolve();
  
  		}
  
  	}
  	/**
   * Materials specular Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_specular
   */
  
  
  	class GLTFMaterialsSpecularExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.KHR_MATERIALS_SPECULAR;
  
  		}
  
  		getMaterialType( materialIndex ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
  			return THREE.MeshPhysicalMaterial;
  
  		}
  
  		extendMaterialParams( materialIndex, materialParams ) {
  
  			const parser = this.parser;
  			const materialDef = parser.json.materials[ materialIndex ];
  
  			if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
  
  				return Promise.resolve();
  
  			}
  
  			const pending = [];
  			const extension = materialDef.extensions[ this.name ];
  			materialParams.specularIntensity = extension.specularFactor !== undefined ? extension.specularFactor : 1.0;
  
  			if ( extension.specularTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'specularIntensityMap', extension.specularTexture ) );
  
  			}
  
  			const colorArray = extension.specularColorFactor || [ 1, 1, 1 ];
  			materialParams.specularColor = new THREE.Color( colorArray[ 0 ], colorArray[ 1 ], colorArray[ 2 ] );
  
  			if ( extension.specularColorTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'specularColorMap', extension.specularColorTexture, THREE.sRGBEncoding ) );
  
  			}
  
  			return Promise.all( pending );
  
  		}
  
  	}
  	/**
   * BasisU THREE.Texture Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_basisu
   */
  
  
  	class GLTFTextureBasisUExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.KHR_TEXTURE_BASISU;
  
  		}
  
  		loadTexture( textureIndex ) {
  
  			const parser = this.parser;
  			const json = parser.json;
  			const textureDef = json.textures[ textureIndex ];
  
  			if ( ! textureDef.extensions || ! textureDef.extensions[ this.name ] ) {
  
  				return null;
  
  			}
  
  			const extension = textureDef.extensions[ this.name ];
  			const loader = parser.options.ktx2Loader;
  
  			if ( ! loader ) {
  
  				if ( json.extensionsRequired && json.extensionsRequired.indexOf( this.name ) >= 0 ) {
  
  					throw new Error( 'THREE.GLTFLoader: setKTX2Loader must be called before loading KTX2 textures' );
  
  				} else {
  
  					// Assumes that the extension is optional and that a fallback texture is present
  					return null;
  
  				}
  
  			}
  
  			return parser.loadTextureImage( textureIndex, extension.source, loader );
  
  		}
  
  	}
  	/**
   * WebP THREE.Texture Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_texture_webp
   */
  
  
  	class GLTFTextureWebPExtension {
  
  		constructor( parser ) {
  
  			this.parser = parser;
  			this.name = EXTENSIONS.EXT_TEXTURE_WEBP;
  			this.isSupported = null;
  
  		}
  
  		loadTexture( textureIndex ) {
  
  			const name = this.name;
  			const parser = this.parser;
  			const json = parser.json;
  			const textureDef = json.textures[ textureIndex ];
  
  			if ( ! textureDef.extensions || ! textureDef.extensions[ name ] ) {
  
  				return null;
  
  			}
  
  			const extension = textureDef.extensions[ name ];
  			const source = json.images[ extension.source ];
  			let loader = parser.textureLoader;
  
  			if ( source.uri ) {
  
  				const handler = parser.options.manager.getHandler( source.uri );
  				if ( handler !== null ) loader = handler;
  
  			}
  
  			return this.detectSupport().then( function ( isSupported ) {
  
  				if ( isSupported ) return parser.loadTextureImage( textureIndex, extension.source, loader );
  
  				if ( json.extensionsRequired && json.extensionsRequired.indexOf( name ) >= 0 ) {
  
  					throw new Error( 'THREE.GLTFLoader: WebP required by asset but unsupported.' );
  
  				} // Fall back to PNG or JPEG.
  
  
  				return parser.loadTexture( textureIndex );
  
  			} );
  
  		}
  
  		detectSupport() {
  
  			if ( ! this.isSupported ) {
  
  				this.isSupported = new Promise( function ( resolve ) {
  
  					const image = new Image(); // Lossy test image. Support for lossy images doesn't guarantee support for all
  					// WebP images, unfortunately.
  
  					image.src = 'data:image/webp;base64,UklGRiIAAABXRUJQVlA4IBYAAAAwAQCdASoBAAEADsD+JaQAA3AAAAAA';
  
  					image.onload = image.onerror = function () {
  
  						resolve( image.height === 1 );
  
  					};
  
  				} );
  
  			}
  
  			return this.isSupported;
  
  		}
  
  	}
  	/**
   * meshopt BufferView Compression Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_meshopt_compression
   */
  
  
  	class GLTFMeshoptCompression {
  
  		constructor( parser ) {
  
  			this.name = EXTENSIONS.EXT_MESHOPT_COMPRESSION;
  			this.parser = parser;
  
  		}
  
  		loadBufferView( index ) {
  
  			const json = this.parser.json;
  			const bufferView = json.bufferViews[ index ];
  
  			if ( bufferView.extensions && bufferView.extensions[ this.name ] ) {
  
  				const extensionDef = bufferView.extensions[ this.name ];
  				const buffer = this.parser.getDependency( 'buffer', extensionDef.buffer );
  				const decoder = this.parser.options.meshoptDecoder;
  
  				if ( ! decoder || ! decoder.supported ) {
  
  					if ( json.extensionsRequired && json.extensionsRequired.indexOf( this.name ) >= 0 ) {
  
  						throw new Error( 'THREE.GLTFLoader: setMeshoptDecoder must be called before loading compressed files' );
  
  					} else {
  
  						// Assumes that the extension is optional and that fallback buffer data is present
  						return null;
  
  					}
  
  				}
  
  				return Promise.all( [ buffer, decoder.ready ] ).then( function ( res ) {
  
  					const byteOffset = extensionDef.byteOffset || 0;
  					const byteLength = extensionDef.byteLength || 0;
  					const count = extensionDef.count;
  					const stride = extensionDef.byteStride;
  					const result = new ArrayBuffer( count * stride );
  					const source = new Uint8Array( res[ 0 ], byteOffset, byteLength );
  					decoder.decodeGltfBuffer( new Uint8Array( result ), count, stride, source, extensionDef.mode, extensionDef.filter );
  					return result;
  
  				} );
  
  			} else {
  
  				return null;
  
  			}
  
  		}
  
  	}
  	/* BINARY EXTENSION */
  
  
  	const BINARY_EXTENSION_HEADER_MAGIC = 'glTF';
  	const BINARY_EXTENSION_HEADER_LENGTH = 12;
  	const BINARY_EXTENSION_CHUNK_TYPES = {
  		JSON: 0x4E4F534A,
  		BIN: 0x004E4942
  	};
  
  	class GLTFBinaryExtension {
  
  		constructor( data ) {
  
  			this.name = EXTENSIONS.KHR_BINARY_GLTF;
  			this.content = null;
  			this.body = null;
  			const headerView = new DataView( data, 0, BINARY_EXTENSION_HEADER_LENGTH );
  			this.header = {
  				magic: THREE.LoaderUtils.decodeText( new Uint8Array( data.slice( 0, 4 ) ) ),
  				version: headerView.getUint32( 4, true ),
  				length: headerView.getUint32( 8, true )
  			};
  
  			if ( this.header.magic !== BINARY_EXTENSION_HEADER_MAGIC ) {
  
  				throw new Error( 'THREE.GLTFLoader: Unsupported glTF-Binary header.' );
  
  			} else if ( this.header.version < 2.0 ) {
  
  				throw new Error( 'THREE.GLTFLoader: Legacy binary file detected.' );
  
  			}
  
  			const chunkContentsLength = this.header.length - BINARY_EXTENSION_HEADER_LENGTH;
  			const chunkView = new DataView( data, BINARY_EXTENSION_HEADER_LENGTH );
  			let chunkIndex = 0;
  
  			while ( chunkIndex < chunkContentsLength ) {
  
  				const chunkLength = chunkView.getUint32( chunkIndex, true );
  				chunkIndex += 4;
  				const chunkType = chunkView.getUint32( chunkIndex, true );
  				chunkIndex += 4;
  
  				if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.JSON ) {
  
  					const contentArray = new Uint8Array( data, BINARY_EXTENSION_HEADER_LENGTH + chunkIndex, chunkLength );
  					this.content = THREE.LoaderUtils.decodeText( contentArray );
  
  				} else if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.BIN ) {
  
  					const byteOffset = BINARY_EXTENSION_HEADER_LENGTH + chunkIndex;
  					this.body = data.slice( byteOffset, byteOffset + chunkLength );
  
  				} // Clients must ignore chunks with unknown types.
  
  
  				chunkIndex += chunkLength;
  
  			}
  
  			if ( this.content === null ) {
  
  				throw new Error( 'THREE.GLTFLoader: JSON content not found.' );
  
  			}
  
  		}
  
  	}
  	/**
   * DRACO THREE.Mesh Compression Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_draco_mesh_compression
   */
  
  
  	class GLTFDracoMeshCompressionExtension {
  
  		constructor( json, dracoLoader ) {
  
  			if ( ! dracoLoader ) {
  
  				throw new Error( 'THREE.GLTFLoader: No DRACOLoader instance provided.' );
  
  			}
  
  			this.name = EXTENSIONS.KHR_DRACO_MESH_COMPRESSION;
  			this.json = json;
  			this.dracoLoader = dracoLoader;
  			this.dracoLoader.preload();
  
  		}
  
  		decodePrimitive( primitive, parser ) {
  
  			const json = this.json;
  			const dracoLoader = this.dracoLoader;
  			const bufferViewIndex = primitive.extensions[ this.name ].bufferView;
  			const gltfAttributeMap = primitive.extensions[ this.name ].attributes;
  			const threeAttributeMap = {};
  			const attributeNormalizedMap = {};
  			const attributeTypeMap = {};
  
  			for ( const attributeName in gltfAttributeMap ) {
  
  				const threeAttributeName = ATTRIBUTES[ attributeName ] || attributeName.toLowerCase();
  				threeAttributeMap[ threeAttributeName ] = gltfAttributeMap[ attributeName ];
  
  			}
  
  			for ( const attributeName in primitive.attributes ) {
  
  				const threeAttributeName = ATTRIBUTES[ attributeName ] || attributeName.toLowerCase();
  
  				if ( gltfAttributeMap[ attributeName ] !== undefined ) {
  
  					const accessorDef = json.accessors[ primitive.attributes[ attributeName ] ];
  					const componentType = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ];
  					attributeTypeMap[ threeAttributeName ] = componentType;
  					attributeNormalizedMap[ threeAttributeName ] = accessorDef.normalized === true;
  
  				}
  
  			}
  
  			return parser.getDependency( 'bufferView', bufferViewIndex ).then( function ( bufferView ) {
  
  				return new Promise( function ( resolve ) {
  
  					dracoLoader.decodeDracoFile( bufferView, function ( geometry ) {
  
  						for ( const attributeName in geometry.attributes ) {
  
  							const attribute = geometry.attributes[ attributeName ];
  							const normalized = attributeNormalizedMap[ attributeName ];
  							if ( normalized !== undefined ) attribute.normalized = normalized;
  
  						}
  
  						resolve( geometry );
  
  					}, threeAttributeMap, attributeTypeMap );
  
  				} );
  
  			} );
  
  		}
  
  	}
  	/**
   * THREE.Texture Transform Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_transform
   */
  
  
  	class GLTFTextureTransformExtension {
  
  		constructor() {
  
  			this.name = EXTENSIONS.KHR_TEXTURE_TRANSFORM;
  
  		}
  
  		extendTexture( texture, transform ) {
  
  			if ( transform.texCoord !== undefined ) {
  
  				console.warn( 'THREE.GLTFLoader: Custom UV sets in "' + this.name + '" extension not yet supported.' );
  
  			}
  
  			if ( transform.offset === undefined && transform.rotation === undefined && transform.scale === undefined ) {
  
  				// See https://github.com/mrdoob/three.js/issues/21819.
  				return texture;
  
  			}
  
  			texture = texture.clone();
  
  			if ( transform.offset !== undefined ) {
  
  				texture.offset.fromArray( transform.offset );
  
  			}
  
  			if ( transform.rotation !== undefined ) {
  
  				texture.rotation = transform.rotation;
  
  			}
  
  			if ( transform.scale !== undefined ) {
  
  				texture.repeat.fromArray( transform.scale );
  
  			}
  
  			texture.needsUpdate = true;
  			return texture;
  
  		}
  
  	}
  	/**
   * Specular-Glossiness Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Archived/KHR_materials_pbrSpecularGlossiness
   */
  
  	/**
   * A sub class of StandardMaterial with some of the functionality
   * changed via the `onBeforeCompile` callback
   * @pailhead
   */
  
  
  	class GLTFMeshStandardSGMaterial extends THREE.MeshStandardMaterial {
  
  		constructor( params ) {
  
  			super();
  			this.isGLTFSpecularGlossinessMaterial = true; //various chunks that need replacing
  
  			const specularMapParsFragmentChunk = [ '#ifdef USE_SPECULARMAP', '	uniform sampler2D specularMap;', '#endif' ].join( '\n' );
  			const glossinessMapParsFragmentChunk = [ '#ifdef USE_GLOSSINESSMAP', '	uniform sampler2D glossinessMap;', '#endif' ].join( '\n' );
  			const specularMapFragmentChunk = [ 'vec3 specularFactor = specular;', '#ifdef USE_SPECULARMAP', '	vec4 texelSpecular = texture2D( specularMap, vUv );', '	// reads channel RGB, compatible with a glTF Specular-Glossiness (RGBA) texture', '	specularFactor *= texelSpecular.rgb;', '#endif' ].join( '\n' );
  			const glossinessMapFragmentChunk = [ 'float glossinessFactor = glossiness;', '#ifdef USE_GLOSSINESSMAP', '	vec4 texelGlossiness = texture2D( glossinessMap, vUv );', '	// reads channel A, compatible with a glTF Specular-Glossiness (RGBA) texture', '	glossinessFactor *= texelGlossiness.a;', '#endif' ].join( '\n' );
  			const lightPhysicalFragmentChunk = [ 'PhysicalMaterial material;', 'material.diffuseColor = diffuseColor.rgb * ( 1. - max( specularFactor.r, max( specularFactor.g, specularFactor.b ) ) );', 'vec3 dxy = max( abs( dFdx( geometryNormal ) ), abs( dFdy( geometryNormal ) ) );', 'float geometryRoughness = max( max( dxy.x, dxy.y ), dxy.z );', 'material.roughness = max( 1.0 - glossinessFactor, 0.0525 ); // 0.0525 corresponds to the base mip of a 256 cubemap.', 'material.roughness += geometryRoughness;', 'material.roughness = min( material.roughness, 1.0 );', 'material.specularColor = specularFactor;' ].join( '\n' );
  			const uniforms = {
  				specular: {
  					value: new THREE.Color().setHex( 0xffffff )
  				},
  				glossiness: {
  					value: 1
  				},
  				specularMap: {
  					value: null
  				},
  				glossinessMap: {
  					value: null
  				}
  			};
  			this._extraUniforms = uniforms;
  
  			this.onBeforeCompile = function ( shader ) {
  
  				for ( const uniformName in uniforms ) {
  
  					shader.uniforms[ uniformName ] = uniforms[ uniformName ];
  
  				}
  
  				shader.fragmentShader = shader.fragmentShader.replace( 'uniform float roughness;', 'uniform vec3 specular;' ).replace( 'uniform float metalness;', 'uniform float glossiness;' ).replace( '#include <roughnessmap_pars_fragment>', specularMapParsFragmentChunk ).replace( '#include <metalnessmap_pars_fragment>', glossinessMapParsFragmentChunk ).replace( '#include <roughnessmap_fragment>', specularMapFragmentChunk ).replace( '#include <metalnessmap_fragment>', glossinessMapFragmentChunk ).replace( '#include <lights_physical_fragment>', lightPhysicalFragmentChunk );
  
  			};
  
  			Object.defineProperties( this, {
  				specular: {
  					get: function () {
  
  						return uniforms.specular.value;
  
  					},
  					set: function ( v ) {
  
  						uniforms.specular.value = v;
  
  					}
  				},
  				specularMap: {
  					get: function () {
  
  						return uniforms.specularMap.value;
  
  					},
  					set: function ( v ) {
  
  						uniforms.specularMap.value = v;
  
  						if ( v ) {
  
  							this.defines.USE_SPECULARMAP = ''; // USE_UV is set by the renderer for specular maps
  
  						} else {
  
  							delete this.defines.USE_SPECULARMAP;
  
  						}
  
  					}
  				},
  				glossiness: {
  					get: function () {
  
  						return uniforms.glossiness.value;
  
  					},
  					set: function ( v ) {
  
  						uniforms.glossiness.value = v;
  
  					}
  				},
  				glossinessMap: {
  					get: function () {
  
  						return uniforms.glossinessMap.value;
  
  					},
  					set: function ( v ) {
  
  						uniforms.glossinessMap.value = v;
  
  						if ( v ) {
  
  							this.defines.USE_GLOSSINESSMAP = '';
  							this.defines.USE_UV = '';
  
  						} else {
  
  							delete this.defines.USE_GLOSSINESSMAP;
  							delete this.defines.USE_UV;
  
  						}
  
  					}
  				}
  			} );
  			delete this.metalness;
  			delete this.roughness;
  			delete this.metalnessMap;
  			delete this.roughnessMap;
  			this.setValues( params );
  
  		}
  
  		copy( source ) {
  
  			super.copy( source );
  			this.specularMap = source.specularMap;
  			this.specular.copy( source.specular );
  			this.glossinessMap = source.glossinessMap;
  			this.glossiness = source.glossiness;
  			delete this.metalness;
  			delete this.roughness;
  			delete this.metalnessMap;
  			delete this.roughnessMap;
  			return this;
  
  		}
  
  	}
  
  	class GLTFMaterialsPbrSpecularGlossinessExtension {
  
  		constructor() {
  
  			this.name = EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS;
  			this.specularGlossinessParams = [ 'color', 'map', 'lightMap', 'lightMapIntensity', 'aoMap', 'aoMapIntensity', 'emissive', 'emissiveIntensity', 'emissiveMap', 'bumpMap', 'bumpScale', 'normalMap', 'normalMapType', 'displacementMap', 'displacementScale', 'displacementBias', 'specularMap', 'specular', 'glossinessMap', 'glossiness', 'alphaMap', 'envMap', 'envMapIntensity' ];
  
  		}
  
  		getMaterialType() {
  
  			return GLTFMeshStandardSGMaterial;
  
  		}
  
  		extendParams( materialParams, materialDef, parser ) {
  
  			const pbrSpecularGlossiness = materialDef.extensions[ this.name ];
  			materialParams.color = new THREE.Color( 1.0, 1.0, 1.0 );
  			materialParams.opacity = 1.0;
  			const pending = [];
  
  			if ( Array.isArray( pbrSpecularGlossiness.diffuseFactor ) ) {
  
  				const array = pbrSpecularGlossiness.diffuseFactor;
  				materialParams.color.fromArray( array );
  				materialParams.opacity = array[ 3 ];
  
  			}
  
  			if ( pbrSpecularGlossiness.diffuseTexture !== undefined ) {
  
  				pending.push( parser.assignTexture( materialParams, 'map', pbrSpecularGlossiness.diffuseTexture, THREE.sRGBEncoding ) );
  
  			}
  
  			materialParams.emissive = new THREE.Color( 0.0, 0.0, 0.0 );
  			materialParams.glossiness = pbrSpecularGlossiness.glossinessFactor !== undefined ? pbrSpecularGlossiness.glossinessFactor : 1.0;
  			materialParams.specular = new THREE.Color( 1.0, 1.0, 1.0 );
  
  			if ( Array.isArray( pbrSpecularGlossiness.specularFactor ) ) {
  
  				materialParams.specular.fromArray( pbrSpecularGlossiness.specularFactor );
  
  			}
  
  			if ( pbrSpecularGlossiness.specularGlossinessTexture !== undefined ) {
  
  				const specGlossMapDef = pbrSpecularGlossiness.specularGlossinessTexture;
  				pending.push( parser.assignTexture( materialParams, 'glossinessMap', specGlossMapDef ) );
  				pending.push( parser.assignTexture( materialParams, 'specularMap', specGlossMapDef, THREE.sRGBEncoding ) );
  
  			}
  
  			return Promise.all( pending );
  
  		}
  
  		createMaterial( materialParams ) {
  
  			const material = new GLTFMeshStandardSGMaterial( materialParams );
  			material.fog = true;
  			material.color = materialParams.color;
  			material.map = materialParams.map === undefined ? null : materialParams.map;
  			material.lightMap = null;
  			material.lightMapIntensity = 1.0;
  			material.aoMap = materialParams.aoMap === undefined ? null : materialParams.aoMap;
  			material.aoMapIntensity = 1.0;
  			material.emissive = materialParams.emissive;
  			material.emissiveIntensity = 1.0;
  			material.emissiveMap = materialParams.emissiveMap === undefined ? null : materialParams.emissiveMap;
  			material.bumpMap = materialParams.bumpMap === undefined ? null : materialParams.bumpMap;
  			material.bumpScale = 1;
  			material.normalMap = materialParams.normalMap === undefined ? null : materialParams.normalMap;
  			material.normalMapType = THREE.TangentSpaceNormalMap;
  			if ( materialParams.normalScale ) material.normalScale = materialParams.normalScale;
  			material.displacementMap = null;
  			material.displacementScale = 1;
  			material.displacementBias = 0;
  			material.specularMap = materialParams.specularMap === undefined ? null : materialParams.specularMap;
  			material.specular = materialParams.specular;
  			material.glossinessMap = materialParams.glossinessMap === undefined ? null : materialParams.glossinessMap;
  			material.glossiness = materialParams.glossiness;
  			material.alphaMap = null;
  			material.envMap = materialParams.envMap === undefined ? null : materialParams.envMap;
  			material.envMapIntensity = 1.0;
  			return material;
  
  		}
  
  	}
  	/**
   * THREE.Mesh Quantization Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization
   */
  
  
  	class GLTFMeshQuantizationExtension {
  
  		constructor() {
  
  			this.name = EXTENSIONS.KHR_MESH_QUANTIZATION;
  
  		}
  
  	}
  	/*********************************/
  
  	/********** INTERPOLATION ********/
  
  	/*********************************/
  	// Spline Interpolation
  	// Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#appendix-c-spline-interpolation
  
  
  	class GLTFCubicSplineInterpolant extends THREE.Interpolant {
  
  		constructor( parameterPositions, sampleValues, sampleSize, resultBuffer ) {
  
  			super( parameterPositions, sampleValues, sampleSize, resultBuffer );
  
  		}
  
  		copySampleValue_( index ) {
  
  			// Copies a sample value to the result buffer. See description of glTF
  			// CUBICSPLINE values layout in interpolate_() function below.
  			const result = this.resultBuffer,
  				values = this.sampleValues,
  				valueSize = this.valueSize,
  				offset = index * valueSize * 3 + valueSize;
  
  			for ( let i = 0; i !== valueSize; i ++ ) {
  
  				result[ i ] = values[ offset + i ];
  
  			}
  
  			return result;
  
  		}
  
  	}
  
  	GLTFCubicSplineInterpolant.prototype.beforeStart_ = GLTFCubicSplineInterpolant.prototype.copySampleValue_;
  	GLTFCubicSplineInterpolant.prototype.afterEnd_ = GLTFCubicSplineInterpolant.prototype.copySampleValue_;
  
  	GLTFCubicSplineInterpolant.prototype.interpolate_ = function ( i1, t0, t, t1 ) {
  
  		const result = this.resultBuffer;
  		const values = this.sampleValues;
  		const stride = this.valueSize;
  		const stride2 = stride * 2;
  		const stride3 = stride * 3;
  		const td = t1 - t0;
  		const p = ( t - t0 ) / td;
  		const pp = p * p;
  		const ppp = pp * p;
  		const offset1 = i1 * stride3;
  		const offset0 = offset1 - stride3;
  		const s2 = - 2 * ppp + 3 * pp;
  		const s3 = ppp - pp;
  		const s0 = 1 - s2;
  		const s1 = s3 - pp + p; // Layout of keyframe output values for CUBICSPLINE animations:
  		//   [ inTangent_1, splineVertex_1, outTangent_1, inTangent_2, splineVertex_2, ... ]
  
  		for ( let i = 0; i !== stride; i ++ ) {
  
  			const p0 = values[ offset0 + i + stride ]; // splineVertex_k
  
  			const m0 = values[ offset0 + i + stride2 ] * td; // outTangent_k * (t_k+1 - t_k)
  
  			const p1 = values[ offset1 + i + stride ]; // splineVertex_k+1
  
  			const m1 = values[ offset1 + i ] * td; // inTangent_k+1 * (t_k+1 - t_k)
  
  			result[ i ] = s0 * p0 + s1 * m0 + s2 * p1 + s3 * m1;
  
  		}
  
  		return result;
  
  	};
  
  	const _q = new THREE.Quaternion();
  
  	class GLTFCubicSplineQuaternionInterpolant extends GLTFCubicSplineInterpolant {
  
  		interpolate_( i1, t0, t, t1 ) {
  
  			const result = super.interpolate_( i1, t0, t, t1 );
  
  			_q.fromArray( result ).normalize().toArray( result );
  
  			return result;
  
  		}
  
  	}
  	/*********************************/
  
  	/********** INTERNALS ************/
  
  	/*********************************/
  
  	/* CONSTANTS */
  
  
  	const WEBGL_CONSTANTS = {
  		FLOAT: 5126,
  		//FLOAT_MAT2: 35674,
  		FLOAT_MAT3: 35675,
  		FLOAT_MAT4: 35676,
  		FLOAT_VEC2: 35664,
  		FLOAT_VEC3: 35665,
  		FLOAT_VEC4: 35666,
  		LINEAR: 9729,
  		REPEAT: 10497,
  		SAMPLER_2D: 35678,
  		POINTS: 0,
  		LINES: 1,
  		LINE_LOOP: 2,
  		LINE_STRIP: 3,
  		TRIANGLES: 4,
  		TRIANGLE_STRIP: 5,
  		TRIANGLE_FAN: 6,
  		UNSIGNED_BYTE: 5121,
  		UNSIGNED_SHORT: 5123
  	};
  	const WEBGL_COMPONENT_TYPES = {
  		5120: Int8Array,
  		5121: Uint8Array,
  		5122: Int16Array,
  		5123: Uint16Array,
  		5125: Uint32Array,
  		5126: Float32Array
  	};
  	const WEBGL_FILTERS = {
  		9728: THREE.NearestFilter,
  		9729: THREE.LinearFilter,
  		9984: THREE.NearestMipmapNearestFilter,
  		9985: THREE.LinearMipmapNearestFilter,
  		9986: THREE.NearestMipmapLinearFilter,
  		9987: THREE.LinearMipmapLinearFilter
  	};
  	const WEBGL_WRAPPINGS = {
  		33071: THREE.ClampToEdgeWrapping,
  		33648: THREE.MirroredRepeatWrapping,
  		10497: THREE.RepeatWrapping
  	};
  	const WEBGL_TYPE_SIZES = {
  		'SCALAR': 1,
  		'VEC2': 2,
  		'VEC3': 3,
  		'VEC4': 4,
  		'MAT2': 4,
  		'MAT3': 9,
  		'MAT4': 16
  	};
  	const ATTRIBUTES = {
  		POSITION: 'position',
  		NORMAL: 'normal',
  		TANGENT: 'tangent',
  		TEXCOORD_0: 'uv',
  		TEXCOORD_1: 'uv2',
  		COLOR_0: 'color',
  		WEIGHTS_0: 'skinWeight',
  		JOINTS_0: 'skinIndex'
  	};
  	const PATH_PROPERTIES = {
  		scale: 'scale',
  		translation: 'position',
  		rotation: 'quaternion',
  		weights: 'morphTargetInfluences'
  	};
  	const INTERPOLATION = {
  		CUBICSPLINE: undefined,
  		// We use a custom interpolant (GLTFCubicSplineInterpolation) for CUBICSPLINE tracks. Each
  		// keyframe track will be initialized with a default interpolation type, then modified.
  		LINEAR: THREE.InterpolateLinear,
  		STEP: THREE.InterpolateDiscrete
  	};
  	const ALPHA_MODES = {
  		OPAQUE: 'OPAQUE',
  		MASK: 'MASK',
  		BLEND: 'BLEND'
  	};
  	/**
   * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#default-material
   */
  
  	function createDefaultMaterial( cache ) {
  
  		if ( cache[ 'DefaultMaterial' ] === undefined ) {
  
  			cache[ 'DefaultMaterial' ] = new THREE.MeshStandardMaterial( {
  				color: 0xFFFFFF,
  				emissive: 0x000000,
  				metalness: 1,
  				roughness: 1,
  				transparent: false,
  				depthTest: true,
  				side: THREE.FrontSide
  			} );
  
  		}
  
  		return cache[ 'DefaultMaterial' ];
  
  	}
  
  	function addUnknownExtensionsToUserData( knownExtensions, object, objectDef ) {
  
  		// Add unknown glTF extensions to an object's userData.
  		for ( const name in objectDef.extensions ) {
  
  			if ( knownExtensions[ name ] === undefined ) {
  
  				object.userData.gltfExtensions = object.userData.gltfExtensions || {};
  				object.userData.gltfExtensions[ name ] = objectDef.extensions[ name ];
  
  			}
  
  		}
  
  	}
  	/**
   * @param {Object3D|Material|BufferGeometry} object
   * @param {GLTF.definition} gltfDef
   */
  
  
  	function assignExtrasToUserData( object, gltfDef ) {
  
  		if ( gltfDef.extras !== undefined ) {
  
  			if ( typeof gltfDef.extras === 'object' ) {
  
  				Object.assign( object.userData, gltfDef.extras );
  
  			} else {
  
  				console.warn( 'THREE.GLTFLoader: Ignoring primitive type .extras, ' + gltfDef.extras );
  
  			}
  
  		}
  
  	}
  	/**
   * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#morph-targets
   *
   * @param {BufferGeometry} geometry
   * @param {Array<GLTF.Target>} targets
   * @param {GLTFParser} parser
   * @return {Promise<BufferGeometry>}
   */
  
  
  	function addMorphTargets( geometry, targets, parser ) {
  
  		let hasMorphPosition = false;
  		let hasMorphNormal = false;
  		let hasMorphColor = false;
  
  		for ( let i = 0, il = targets.length; i < il; i ++ ) {
  
  			const target = targets[ i ];
  			if ( target.POSITION !== undefined ) hasMorphPosition = true;
  			if ( target.NORMAL !== undefined ) hasMorphNormal = true;
  			if ( target.COLOR_0 !== undefined ) hasMorphColor = true;
  			if ( hasMorphPosition && hasMorphNormal && hasMorphColor ) break;
  
  		}
  
  		if ( ! hasMorphPosition && ! hasMorphNormal && ! hasMorphColor ) return Promise.resolve( geometry );
  		const pendingPositionAccessors = [];
  		const pendingNormalAccessors = [];
  		const pendingColorAccessors = [];
  
  		for ( let i = 0, il = targets.length; i < il; i ++ ) {
  
  			const target = targets[ i ];
  
  			if ( hasMorphPosition ) {
  
  				const pendingAccessor = target.POSITION !== undefined ? parser.getDependency( 'accessor', target.POSITION ) : geometry.attributes.position;
  				pendingPositionAccessors.push( pendingAccessor );
  
  			}
  
  			if ( hasMorphNormal ) {
  
  				const pendingAccessor = target.NORMAL !== undefined ? parser.getDependency( 'accessor', target.NORMAL ) : geometry.attributes.normal;
  				pendingNormalAccessors.push( pendingAccessor );
  
  			}
  
  			if ( hasMorphColor ) {
  
  				const pendingAccessor = target.COLOR_0 !== undefined ? parser.getDependency( 'accessor', target.COLOR_0 ) : geometry.attributes.color;
  				pendingColorAccessors.push( pendingAccessor );
  
  			}
  
  		}
  
  		return Promise.all( [ Promise.all( pendingPositionAccessors ), Promise.all( pendingNormalAccessors ), Promise.all( pendingColorAccessors ) ] ).then( function ( accessors ) {
  
  			const morphPositions = accessors[ 0 ];
  			const morphNormals = accessors[ 1 ];
  			const morphColors = accessors[ 2 ];
  			if ( hasMorphPosition ) geometry.morphAttributes.position = morphPositions;
  			if ( hasMorphNormal ) geometry.morphAttributes.normal = morphNormals;
  			if ( hasMorphColor ) geometry.morphAttributes.color = morphColors;
  			geometry.morphTargetsRelative = true;
  			return geometry;
  
  		} );
  
  	}
  	/**
   * @param {Mesh} mesh
   * @param {GLTF.Mesh} meshDef
   */
  
  
  	function updateMorphTargets( mesh, meshDef ) {
  
  		mesh.updateMorphTargets();
  
  		if ( meshDef.weights !== undefined ) {
  
  			for ( let i = 0, il = meshDef.weights.length; i < il; i ++ ) {
  
  				mesh.morphTargetInfluences[ i ] = meshDef.weights[ i ];
  
  			}
  
  		} // .extras has user-defined data, so check that .extras.targetNames is an array.
  
  
  		if ( meshDef.extras && Array.isArray( meshDef.extras.targetNames ) ) {
  
  			const targetNames = meshDef.extras.targetNames;
  
  			if ( mesh.morphTargetInfluences.length === targetNames.length ) {
  
  				mesh.morphTargetDictionary = {};
  
  				for ( let i = 0, il = targetNames.length; i < il; i ++ ) {
  
  					mesh.morphTargetDictionary[ targetNames[ i ] ] = i;
  
  				}
  
  			} else {
  
  				console.warn( 'THREE.GLTFLoader: Invalid extras.targetNames length. Ignoring names.' );
  
  			}
  
  		}
  
  	}
  
  	function createPrimitiveKey( primitiveDef ) {
  
  		const dracoExtension = primitiveDef.extensions && primitiveDef.extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ];
  		let geometryKey;
  
  		if ( dracoExtension ) {
  
  			geometryKey = 'draco:' + dracoExtension.bufferView + ':' + dracoExtension.indices + ':' + createAttributesKey( dracoExtension.attributes );
  
  		} else {
  
  			geometryKey = primitiveDef.indices + ':' + createAttributesKey( primitiveDef.attributes ) + ':' + primitiveDef.mode;
  
  		}
  
  		return geometryKey;
  
  	}
  
  	function createAttributesKey( attributes ) {
  
  		let attributesKey = '';
  		const keys = Object.keys( attributes ).sort();
  
  		for ( let i = 0, il = keys.length; i < il; i ++ ) {
  
  			attributesKey += keys[ i ] + ':' + attributes[ keys[ i ] ] + ';';
  
  		}
  
  		return attributesKey;
  
  	}
  
  	function getNormalizedComponentScale( constructor ) {
  
  		// Reference:
  		// https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization#encoding-quantized-data
  		switch ( constructor ) {
  
  			case Int8Array:
  				return 1 / 127;
  
  			case Uint8Array:
  				return 1 / 255;
  
  			case Int16Array:
  				return 1 / 32767;
  
  			case Uint16Array:
  				return 1 / 65535;
  
  			default:
  				throw new Error( 'THREE.GLTFLoader: Unsupported normalized accessor component type.' );
  
  		}
  
  	}
  
  	function getImageURIMimeType( uri ) {
  
  		if ( uri.search( /\.jpe?g($|\?)/i ) > 0 || uri.search( /^data\:image\/jpeg/ ) === 0 ) return 'image/jpeg';
  		if ( uri.search( /\.webp($|\?)/i ) > 0 || uri.search( /^data\:image\/webp/ ) === 0 ) return 'image/webp';
  		return 'image/png';
  
  	}
  	/* GLTF PARSER */
  
  
  	class GLTFParser {
  
  		constructor( json = {}, options = {} ) {
  
  			this.json = json;
  			this.extensions = {};
  			this.plugins = {};
  			this.options = options; // loader object cache
  
  			this.cache = new GLTFRegistry(); // associations between Three.js objects and glTF elements
  
  			this.associations = new Map(); // THREE.BufferGeometry caching
  
  			this.primitiveCache = {}; // THREE.Object3D instance caches
  
  			this.meshCache = {
  				refs: {},
  				uses: {}
  			};
  			this.cameraCache = {
  				refs: {},
  				uses: {}
  			};
  			this.lightCache = {
  				refs: {},
  				uses: {}
  			};
  			this.sourceCache = {};
  			this.textureCache = {}; // Track node names, to ensure no duplicates
  
  			this.nodeNamesUsed = {}; // Use an THREE.ImageBitmapLoader if imageBitmaps are supported. Moves much of the
  			// expensive work of uploading a texture to the GPU off the main thread.
  
  			if ( typeof createImageBitmap !== 'undefined' && /^((?!chrome|android).)*safari/i.test( navigator.userAgent ) === false ) {
  
  				this.textureLoader = new THREE.ImageBitmapLoader( this.options.manager );
  
  			} else {
  
  				this.textureLoader = new THREE.TextureLoader( this.options.manager );
  
  			}
  
  			this.textureLoader.setCrossOrigin( this.options.crossOrigin );
  			this.textureLoader.setRequestHeader( this.options.requestHeader );
  			this.fileLoader = new THREE.FileLoader( this.options.manager );
  			this.fileLoader.setResponseType( 'arraybuffer' );
  
  			if ( this.options.crossOrigin === 'use-credentials' ) {
  
  				this.fileLoader.setWithCredentials( true );
  
  			}
  
  		}
  
  		setExtensions( extensions ) {
  
  			this.extensions = extensions;
  
  		}
  
  		setPlugins( plugins ) {
  
  			this.plugins = plugins;
  
  		}
  
  		parse( onLoad, onError ) {
  
  			const parser = this;
  			const json = this.json;
  			const extensions = this.extensions; // Clear the loader cache
  
  			this.cache.removeAll(); // Mark the special nodes/meshes in json for efficient parse
  
  			this._invokeAll( function ( ext ) {
  
  				return ext._markDefs && ext._markDefs();
  
  			} );
  
  			Promise.all( this._invokeAll( function ( ext ) {
  
  				return ext.beforeRoot && ext.beforeRoot();
  
  			} ) ).then( function () {
  
  				return Promise.all( [ parser.getDependencies( 'scene' ), parser.getDependencies( 'animation' ), parser.getDependencies( 'camera' ) ] );
  
  			} ).then( function ( dependencies ) {
  
  				const result = {
  					scene: dependencies[ 0 ][ json.scene || 0 ],
  					scenes: dependencies[ 0 ],
  					animations: dependencies[ 1 ],
  					cameras: dependencies[ 2 ],
  					asset: json.asset,
  					parser: parser,
  					userData: {}
  				};
  				addUnknownExtensionsToUserData( extensions, result, json );
  				assignExtrasToUserData( result, json );
  				Promise.all( parser._invokeAll( function ( ext ) {
  
  					return ext.afterRoot && ext.afterRoot( result );
  
  				} ) ).then( function () {
  
  					onLoad( result );
  
  				} );
  
  			} ).catch( onError );
  
  		}
  		/**
     * Marks the special nodes/meshes in json for efficient parse.
     */
  
  
  		_markDefs() {
  
  			const nodeDefs = this.json.nodes || [];
  			const skinDefs = this.json.skins || [];
  			const meshDefs = this.json.meshes || []; // Nothing in the node definition indicates whether it is a THREE.Bone or an
  			// THREE.Object3D. Use the skins' joint references to mark bones.
  
  			for ( let skinIndex = 0, skinLength = skinDefs.length; skinIndex < skinLength; skinIndex ++ ) {
  
  				const joints = skinDefs[ skinIndex ].joints;
  
  				for ( let i = 0, il = joints.length; i < il; i ++ ) {
  
  					nodeDefs[ joints[ i ] ].isBone = true;
  
  				}
  
  			} // Iterate over all nodes, marking references to shared resources,
  			// as well as skeleton joints.
  
  
  			for ( let nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex ++ ) {
  
  				const nodeDef = nodeDefs[ nodeIndex ];
  
  				if ( nodeDef.mesh !== undefined ) {
  
  					this._addNodeRef( this.meshCache, nodeDef.mesh ); // Nothing in the mesh definition indicates whether it is
  					// a THREE.SkinnedMesh or THREE.Mesh. Use the node's mesh reference
  					// to mark THREE.SkinnedMesh if node has skin.
  
  
  					if ( nodeDef.skin !== undefined ) {
  
  						meshDefs[ nodeDef.mesh ].isSkinnedMesh = true;
  
  					}
  
  				}
  
  				if ( nodeDef.camera !== undefined ) {
  
  					this._addNodeRef( this.cameraCache, nodeDef.camera );
  
  				}
  
  			}
  
  		}
  		/**
     * Counts references to shared node / THREE.Object3D resources. These resources
     * can be reused, or "instantiated", at multiple nodes in the scene
     * hierarchy. THREE.Mesh, Camera, and Light instances are instantiated and must
     * be marked. Non-scenegraph resources (like Materials, Geometries, and
     * Textures) can be reused directly and are not marked here.
     *
     * Example: CesiumMilkTruck sample model reuses "Wheel" meshes.
     */
  
  
  		_addNodeRef( cache, index ) {
  
  			if ( index === undefined ) return;
  
  			if ( cache.refs[ index ] === undefined ) {
  
  				cache.refs[ index ] = cache.uses[ index ] = 0;
  
  			}
  
  			cache.refs[ index ] ++;
  
  		}
  		/** Returns a reference to a shared resource, cloning it if necessary. */
  
  
  		_getNodeRef( cache, index, object ) {
  
  			if ( cache.refs[ index ] <= 1 ) return object;
  			const ref = object.clone(); // Propagates mappings to the cloned object, prevents mappings on the
  			// original object from being lost.
  
  			const updateMappings = ( original, clone ) => {
  
  				const mappings = this.associations.get( original );
  
  				if ( mappings != null ) {
  
  					this.associations.set( clone, mappings );
  
  				}
  
  				for ( const [ i, child ] of original.children.entries() ) {
  
  					updateMappings( child, clone.children[ i ] );
  
  				}
  
  			};
  
  			updateMappings( object, ref );
  			ref.name += '_instance_' + cache.uses[ index ] ++;
  			return ref;
  
  		}
  
  		_invokeOne( func ) {
  
  			const extensions = Object.values( this.plugins );
  			extensions.push( this );
  
  			for ( let i = 0; i < extensions.length; i ++ ) {
  
  				const result = func( extensions[ i ] );
  				if ( result ) return result;
  
  			}
  
  			return null;
  
  		}
  
  		_invokeAll( func ) {
  
  			const extensions = Object.values( this.plugins );
  			extensions.unshift( this );
  			const pending = [];
  
  			for ( let i = 0; i < extensions.length; i ++ ) {
  
  				const result = func( extensions[ i ] );
  				if ( result ) pending.push( result );
  
  			}
  
  			return pending;
  
  		}
  		/**
     * Requests the specified dependency asynchronously, with caching.
     * @param {string} type
     * @param {number} index
     * @return {Promise<Object3D|Material|THREE.Texture|AnimationClip|ArrayBuffer|Object>}
     */
  
  
  		getDependency( type, index ) {
  
  			const cacheKey = type + ':' + index;
  			let dependency = this.cache.get( cacheKey );
  
  			if ( ! dependency ) {
  
  				switch ( type ) {
  
  					case 'scene':
  						dependency = this.loadScene( index );
  						break;
  
  					case 'node':
  						dependency = this.loadNode( index );
  						break;
  
  					case 'mesh':
  						dependency = this._invokeOne( function ( ext ) {
  
  							return ext.loadMesh && ext.loadMesh( index );
  
  						} );
  						break;
  
  					case 'accessor':
  						dependency = this.loadAccessor( index );
  						break;
  
  					case 'bufferView':
  						dependency = this._invokeOne( function ( ext ) {
  
  							return ext.loadBufferView && ext.loadBufferView( index );
  
  						} );
  						break;
  
  					case 'buffer':
  						dependency = this.loadBuffer( index );
  						break;
  
  					case 'material':
  						dependency = this._invokeOne( function ( ext ) {
  
  							return ext.loadMaterial && ext.loadMaterial( index );
  
  						} );
  						break;
  
  					case 'texture':
  						dependency = this._invokeOne( function ( ext ) {
  
  							return ext.loadTexture && ext.loadTexture( index );
  
  						} );
  						break;
  
  					case 'skin':
  						dependency = this.loadSkin( index );
  						break;
  
  					case 'animation':
  						dependency = this._invokeOne( function ( ext ) {
  
  							return ext.loadAnimation && ext.loadAnimation( index );
  
  						} );
  						break;
  
  					case 'camera':
  						dependency = this.loadCamera( index );
  						break;
  
  					default:
  						throw new Error( 'Unknown type: ' + type );
  
  				}
  
  				this.cache.add( cacheKey, dependency );
  
  			}
  
  			return dependency;
  
  		}
  		/**
     * Requests all dependencies of the specified type asynchronously, with caching.
     * @param {string} type
     * @return {Promise<Array<Object>>}
     */
  
  
  		getDependencies( type ) {
  
  			let dependencies = this.cache.get( type );
  
  			if ( ! dependencies ) {
  
  				const parser = this;
  				const defs = this.json[ type + ( type === 'mesh' ? 'es' : 's' ) ] || [];
  				dependencies = Promise.all( defs.map( function ( def, index ) {
  
  					return parser.getDependency( type, index );
  
  				} ) );
  				this.cache.add( type, dependencies );
  
  			}
  
  			return dependencies;
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
     * @param {number} bufferIndex
     * @return {Promise<ArrayBuffer>}
     */
  
  
  		loadBuffer( bufferIndex ) {
  
  			const bufferDef = this.json.buffers[ bufferIndex ];
  			const loader = this.fileLoader;
  
  			if ( bufferDef.type && bufferDef.type !== 'arraybuffer' ) {
  
  				throw new Error( 'THREE.GLTFLoader: ' + bufferDef.type + ' buffer type is not supported.' );
  
  			} // If present, GLB container is required to be the first buffer.
  
  
  			if ( bufferDef.uri === undefined && bufferIndex === 0 ) {
  
  				return Promise.resolve( this.extensions[ EXTENSIONS.KHR_BINARY_GLTF ].body );
  
  			}
  
  			const options = this.options;
  			return new Promise( function ( resolve, reject ) {
  
  				loader.load( THREE.LoaderUtils.resolveURL( bufferDef.uri, options.path ), resolve, undefined, function () {
  
  					reject( new Error( 'THREE.GLTFLoader: Failed to load buffer "' + bufferDef.uri + '".' ) );
  
  				} );
  
  			} );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
     * @param {number} bufferViewIndex
     * @return {Promise<ArrayBuffer>}
     */
  
  
  		loadBufferView( bufferViewIndex ) {
  
  			const bufferViewDef = this.json.bufferViews[ bufferViewIndex ];
  			return this.getDependency( 'buffer', bufferViewDef.buffer ).then( function ( buffer ) {
  
  				const byteLength = bufferViewDef.byteLength || 0;
  				const byteOffset = bufferViewDef.byteOffset || 0;
  				return buffer.slice( byteOffset, byteOffset + byteLength );
  
  			} );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#accessors
     * @param {number} accessorIndex
     * @return {Promise<BufferAttribute|InterleavedBufferAttribute>}
     */
  
  
  		loadAccessor( accessorIndex ) {
  
  			const parser = this;
  			const json = this.json;
  			const accessorDef = this.json.accessors[ accessorIndex ];
  
  			if ( accessorDef.bufferView === undefined && accessorDef.sparse === undefined ) {
  
  				// Ignore empty accessors, which may be used to declare runtime
  				// information about attributes coming from another source (e.g. Draco
  				// compression extension).
  				return Promise.resolve( null );
  
  			}
  
  			const pendingBufferViews = [];
  
  			if ( accessorDef.bufferView !== undefined ) {
  
  				pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.bufferView ) );
  
  			} else {
  
  				pendingBufferViews.push( null );
  
  			}
  
  			if ( accessorDef.sparse !== undefined ) {
  
  				pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.indices.bufferView ) );
  				pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.values.bufferView ) );
  
  			}
  
  			return Promise.all( pendingBufferViews ).then( function ( bufferViews ) {
  
  				const bufferView = bufferViews[ 0 ];
  				const itemSize = WEBGL_TYPE_SIZES[ accessorDef.type ];
  				const TypedArray = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ]; // For VEC3: itemSize is 3, elementBytes is 4, itemBytes is 12.
  
  				const elementBytes = TypedArray.BYTES_PER_ELEMENT;
  				const itemBytes = elementBytes * itemSize;
  				const byteOffset = accessorDef.byteOffset || 0;
  				const byteStride = accessorDef.bufferView !== undefined ? json.bufferViews[ accessorDef.bufferView ].byteStride : undefined;
  				const normalized = accessorDef.normalized === true;
  				let array, bufferAttribute; // The buffer is not interleaved if the stride is the item size in bytes.
  
  				if ( byteStride && byteStride !== itemBytes ) {
  
  					// Each "slice" of the buffer, as defined by 'count' elements of 'byteStride' bytes, gets its own THREE.InterleavedBuffer
  					// This makes sure that IBA.count reflects accessor.count properly
  					const ibSlice = Math.floor( byteOffset / byteStride );
  					const ibCacheKey = 'InterleavedBuffer:' + accessorDef.bufferView + ':' + accessorDef.componentType + ':' + ibSlice + ':' + accessorDef.count;
  					let ib = parser.cache.get( ibCacheKey );
  
  					if ( ! ib ) {
  
  						array = new TypedArray( bufferView, ibSlice * byteStride, accessorDef.count * byteStride / elementBytes ); // Integer parameters to IB/IBA are in array elements, not bytes.
  
  						ib = new THREE.InterleavedBuffer( array, byteStride / elementBytes );
  						parser.cache.add( ibCacheKey, ib );
  
  					}
  
  					bufferAttribute = new THREE.InterleavedBufferAttribute( ib, itemSize, byteOffset % byteStride / elementBytes, normalized );
  
  				} else {
  
  					if ( bufferView === null ) {
  
  						array = new TypedArray( accessorDef.count * itemSize );
  
  					} else {
  
  						array = new TypedArray( bufferView, byteOffset, accessorDef.count * itemSize );
  
  					}
  
  					bufferAttribute = new THREE.BufferAttribute( array, itemSize, normalized );
  
  				} // https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#sparse-accessors
  
  
  				if ( accessorDef.sparse !== undefined ) {
  
  					const itemSizeIndices = WEBGL_TYPE_SIZES.SCALAR;
  					const TypedArrayIndices = WEBGL_COMPONENT_TYPES[ accessorDef.sparse.indices.componentType ];
  					const byteOffsetIndices = accessorDef.sparse.indices.byteOffset || 0;
  					const byteOffsetValues = accessorDef.sparse.values.byteOffset || 0;
  					const sparseIndices = new TypedArrayIndices( bufferViews[ 1 ], byteOffsetIndices, accessorDef.sparse.count * itemSizeIndices );
  					const sparseValues = new TypedArray( bufferViews[ 2 ], byteOffsetValues, accessorDef.sparse.count * itemSize );
  
  					if ( bufferView !== null ) {
  
  						// Avoid modifying the original ArrayBuffer, if the bufferView wasn't initialized with zeroes.
  						bufferAttribute = new THREE.BufferAttribute( bufferAttribute.array.slice(), bufferAttribute.itemSize, bufferAttribute.normalized );
  
  					}
  
  					for ( let i = 0, il = sparseIndices.length; i < il; i ++ ) {
  
  						const index = sparseIndices[ i ];
  						bufferAttribute.setX( index, sparseValues[ i * itemSize ] );
  						if ( itemSize >= 2 ) bufferAttribute.setY( index, sparseValues[ i * itemSize + 1 ] );
  						if ( itemSize >= 3 ) bufferAttribute.setZ( index, sparseValues[ i * itemSize + 2 ] );
  						if ( itemSize >= 4 ) bufferAttribute.setW( index, sparseValues[ i * itemSize + 3 ] );
  						if ( itemSize >= 5 ) throw new Error( 'THREE.GLTFLoader: Unsupported itemSize in sparse THREE.BufferAttribute.' );
  
  					}
  
  				}
  
  				return bufferAttribute;
  
  			} );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#textures
     * @param {number} textureIndex
     * @return {Promise<THREE.Texture>}
     */
  
  
  		loadTexture( textureIndex ) {
  
  			const json = this.json;
  			const options = this.options;
  			const textureDef = json.textures[ textureIndex ];
  			const sourceIndex = textureDef.source;
  			const sourceDef = json.images[ sourceIndex ];
  			let loader = this.textureLoader;
  
  			if ( sourceDef.uri ) {
  
  				const handler = options.manager.getHandler( sourceDef.uri );
  				if ( handler !== null ) loader = handler;
  
  			}
  
  			return this.loadTextureImage( textureIndex, sourceIndex, loader );
  
  		}
  
  		loadTextureImage( textureIndex, sourceIndex, loader ) {
  
  			const parser = this;
  			const json = this.json;
  			const textureDef = json.textures[ textureIndex ];
  			const sourceDef = json.images[ sourceIndex ];
  			const cacheKey = ( sourceDef.uri || sourceDef.bufferView ) + ':' + textureDef.sampler;
  
  			if ( this.textureCache[ cacheKey ] ) {
  
  				// See https://github.com/mrdoob/three.js/issues/21559.
  				return this.textureCache[ cacheKey ];
  
  			}
  
  			const promise = this.loadImageSource( sourceIndex, loader ).then( function ( texture ) {
  
  				texture.flipY = false;
  				if ( textureDef.name ) texture.name = textureDef.name;
  				const samplers = json.samplers || {};
  				const sampler = samplers[ textureDef.sampler ] || {};
  				texture.magFilter = WEBGL_FILTERS[ sampler.magFilter ] || THREE.LinearFilter;
  				texture.minFilter = WEBGL_FILTERS[ sampler.minFilter ] || THREE.LinearMipmapLinearFilter;
  				texture.wrapS = WEBGL_WRAPPINGS[ sampler.wrapS ] || THREE.RepeatWrapping;
  				texture.wrapT = WEBGL_WRAPPINGS[ sampler.wrapT ] || THREE.RepeatWrapping;
  				parser.associations.set( texture, {
  					textures: textureIndex
  				} );
  				return texture;
  
  			} ).catch( function () {
  
  				return null;
  
  			} );
  			this.textureCache[ cacheKey ] = promise;
  			return promise;
  
  		}
  
  		loadImageSource( sourceIndex, loader ) {
  
  			const parser = this;
  			const json = this.json;
  			const options = this.options;
  
  			if ( this.sourceCache[ sourceIndex ] !== undefined ) {
  
  				return this.sourceCache[ sourceIndex ].then( texture => texture.clone() );
  
  			}
  
  			const sourceDef = json.images[ sourceIndex ];
  			const URL = self.URL || self.webkitURL;
  			let sourceURI = sourceDef.uri || '';
  			let isObjectURL = false;
  
  			if ( sourceDef.bufferView !== undefined ) {
  
  				// Load binary image data from bufferView, if provided.
  				sourceURI = parser.getDependency( 'bufferView', sourceDef.bufferView ).then( function ( bufferView ) {
  
  					isObjectURL = true;
  					const blob = new Blob( [ bufferView ], {
  						type: sourceDef.mimeType
  					} );
  					sourceURI = URL.createObjectURL( blob );
  					return sourceURI;
  
  				} );
  
  			} else if ( sourceDef.uri === undefined ) {
  
  				throw new Error( 'THREE.GLTFLoader: Image ' + sourceIndex + ' is missing URI and bufferView' );
  
  			}
  
  			const promise = Promise.resolve( sourceURI ).then( function ( sourceURI ) {
  
  				return new Promise( function ( resolve, reject ) {
  
  					let onLoad = resolve;
  
  					if ( loader.isImageBitmapLoader === true ) {
  
  						onLoad = function ( imageBitmap ) {
  
  							const texture = new THREE.Texture( imageBitmap );
  							texture.needsUpdate = true;
  							resolve( texture );
  
  						};
  
  					}
  
  					loader.load( THREE.LoaderUtils.resolveURL( sourceURI, options.path ), onLoad, undefined, reject );
  
  				} );
  
  			} ).then( function ( texture ) {
  
  				// Clean up resources and configure THREE.Texture.
  				if ( isObjectURL === true ) {
  
  					URL.revokeObjectURL( sourceURI );
  
  				}
  
  				texture.userData.mimeType = sourceDef.mimeType || getImageURIMimeType( sourceDef.uri );
  				return texture;
  
  			} ).catch( function ( error ) {
  
  				console.error( 'THREE.GLTFLoader: Couldn\'t load texture', sourceURI );
  				throw error;
  
  			} );
  			this.sourceCache[ sourceIndex ] = promise;
  			return promise;
  
  		}
  		/**
     * Asynchronously assigns a texture to the given material parameters.
     * @param {Object} materialParams
     * @param {string} mapName
     * @param {Object} mapDef
     * @return {Promise<Texture>}
     */
  
  
  		assignTexture( materialParams, mapName, mapDef, encoding ) {
  
  			const parser = this;
  			return this.getDependency( 'texture', mapDef.index ).then( function ( texture ) {
  
  				// Materials sample aoMap from UV set 1 and other maps from UV set 0 - this can't be configured
  				// However, we will copy UV set 0 to UV set 1 on demand for aoMap
  				if ( mapDef.texCoord !== undefined && mapDef.texCoord != 0 && ! ( mapName === 'aoMap' && mapDef.texCoord == 1 ) ) {
  
  					console.warn( 'THREE.GLTFLoader: Custom UV set ' + mapDef.texCoord + ' for texture ' + mapName + ' not yet supported.' );
  
  				}
  
  				if ( parser.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ] ) {
  
  					const transform = mapDef.extensions !== undefined ? mapDef.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ] : undefined;
  
  					if ( transform ) {
  
  						const gltfReference = parser.associations.get( texture );
  						texture = parser.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ].extendTexture( texture, transform );
  						parser.associations.set( texture, gltfReference );
  
  					}
  
  				}
  
  				if ( encoding !== undefined ) {
  
  					texture.encoding = encoding;
  
  				}
  
  				materialParams[ mapName ] = texture;
  				return texture;
  
  			} );
  
  		}
  		/**
     * Assigns final material to a THREE.Mesh, THREE.Line, or THREE.Points instance. The instance
     * already has a material (generated from the glTF material options alone)
     * but reuse of the same glTF material may require multiple threejs materials
     * to accommodate different primitive types, defines, etc. New materials will
     * be created if necessary, and reused from a cache.
     * @param  {Object3D} mesh THREE.Mesh, THREE.Line, or THREE.Points instance.
     */
  
  
  		assignFinalMaterial( mesh ) {
  
  			const geometry = mesh.geometry;
  			let material = mesh.material;
  			const useDerivativeTangents = geometry.attributes.tangent === undefined;
  			const useVertexColors = geometry.attributes.color !== undefined;
  			const useFlatShading = geometry.attributes.normal === undefined;
  
  			if ( mesh.isPoints ) {
  
  				const cacheKey = 'PointsMaterial:' + material.uuid;
  				let pointsMaterial = this.cache.get( cacheKey );
  
  				if ( ! pointsMaterial ) {
  
  					pointsMaterial = new THREE.PointsMaterial();
  					THREE.Material.prototype.copy.call( pointsMaterial, material );
  					pointsMaterial.color.copy( material.color );
  					pointsMaterial.map = material.map;
  					pointsMaterial.sizeAttenuation = false; // glTF spec says points should be 1px
  
  					this.cache.add( cacheKey, pointsMaterial );
  
  				}
  
  				material = pointsMaterial;
  
  			} else if ( mesh.isLine ) {
  
  				const cacheKey = 'LineBasicMaterial:' + material.uuid;
  				let lineMaterial = this.cache.get( cacheKey );
  
  				if ( ! lineMaterial ) {
  
  					lineMaterial = new THREE.LineBasicMaterial();
  					THREE.Material.prototype.copy.call( lineMaterial, material );
  					lineMaterial.color.copy( material.color );
  					this.cache.add( cacheKey, lineMaterial );
  
  				}
  
  				material = lineMaterial;
  
  			} // Clone the material if it will be modified
  
  
  			if ( useDerivativeTangents || useVertexColors || useFlatShading ) {
  
  				let cacheKey = 'ClonedMaterial:' + material.uuid + ':';
  				if ( material.isGLTFSpecularGlossinessMaterial ) cacheKey += 'specular-glossiness:';
  				if ( useDerivativeTangents ) cacheKey += 'derivative-tangents:';
  				if ( useVertexColors ) cacheKey += 'vertex-colors:';
  				if ( useFlatShading ) cacheKey += 'flat-shading:';
  				let cachedMaterial = this.cache.get( cacheKey );
  
  				if ( ! cachedMaterial ) {
  
  					cachedMaterial = material.clone();
  					if ( useVertexColors ) cachedMaterial.vertexColors = true;
  					if ( useFlatShading ) cachedMaterial.flatShading = true;
  
  					if ( useDerivativeTangents ) {
  
  						// https://github.com/mrdoob/three.js/issues/11438#issuecomment-507003995
  						if ( cachedMaterial.normalScale ) cachedMaterial.normalScale.y *= - 1;
  						if ( cachedMaterial.clearcoatNormalScale ) cachedMaterial.clearcoatNormalScale.y *= - 1;
  
  					}
  
  					this.cache.add( cacheKey, cachedMaterial );
  					this.associations.set( cachedMaterial, this.associations.get( material ) );
  
  				}
  
  				material = cachedMaterial;
  
  			} // workarounds for mesh and geometry
  
  
  			if ( material.aoMap && geometry.attributes.uv2 === undefined && geometry.attributes.uv !== undefined ) {
  
  				geometry.setAttribute( 'uv2', geometry.attributes.uv );
  
  			}
  
  			mesh.material = material;
  
  		}
  
  		getMaterialType() {
  
  			return THREE.MeshStandardMaterial;
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#materials
     * @param {number} materialIndex
     * @return {Promise<Material>}
     */
  
  
  		loadMaterial( materialIndex ) {
  
  			const parser = this;
  			const json = this.json;
  			const extensions = this.extensions;
  			const materialDef = json.materials[ materialIndex ];
  			let materialType;
  			const materialParams = {};
  			const materialExtensions = materialDef.extensions || {};
  			const pending = [];
  
  			if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ] ) {
  
  				const sgExtension = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ];
  				materialType = sgExtension.getMaterialType();
  				pending.push( sgExtension.extendParams( materialParams, materialDef, parser ) );
  
  			} else if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_UNLIT ] ) {
  
  				const kmuExtension = extensions[ EXTENSIONS.KHR_MATERIALS_UNLIT ];
  				materialType = kmuExtension.getMaterialType();
  				pending.push( kmuExtension.extendParams( materialParams, materialDef, parser ) );
  
  			} else {
  
  				// Specification:
  				// https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material
  				const metallicRoughness = materialDef.pbrMetallicRoughness || {};
  				materialParams.color = new THREE.Color( 1.0, 1.0, 1.0 );
  				materialParams.opacity = 1.0;
  
  				if ( Array.isArray( metallicRoughness.baseColorFactor ) ) {
  
  					const array = metallicRoughness.baseColorFactor;
  					materialParams.color.fromArray( array );
  					materialParams.opacity = array[ 3 ];
  
  				}
  
  				if ( metallicRoughness.baseColorTexture !== undefined ) {
  
  					pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture, THREE.sRGBEncoding ) );
  
  				}
  
  				materialParams.metalness = metallicRoughness.metallicFactor !== undefined ? metallicRoughness.metallicFactor : 1.0;
  				materialParams.roughness = metallicRoughness.roughnessFactor !== undefined ? metallicRoughness.roughnessFactor : 1.0;
  
  				if ( metallicRoughness.metallicRoughnessTexture !== undefined ) {
  
  					pending.push( parser.assignTexture( materialParams, 'metalnessMap', metallicRoughness.metallicRoughnessTexture ) );
  					pending.push( parser.assignTexture( materialParams, 'roughnessMap', metallicRoughness.metallicRoughnessTexture ) );
  
  				}
  
  				materialType = this._invokeOne( function ( ext ) {
  
  					return ext.getMaterialType && ext.getMaterialType( materialIndex );
  
  				} );
  				pending.push( Promise.all( this._invokeAll( function ( ext ) {
  
  					return ext.extendMaterialParams && ext.extendMaterialParams( materialIndex, materialParams );
  
  				} ) ) );
  
  			}
  
  			if ( materialDef.doubleSided === true ) {
  
  				materialParams.side = THREE.DoubleSide;
  
  			}
  
  			const alphaMode = materialDef.alphaMode || ALPHA_MODES.OPAQUE;
  
  			if ( alphaMode === ALPHA_MODES.BLEND ) {
  
  				materialParams.transparent = true; // See: https://github.com/mrdoob/three.js/issues/17706
  
  				materialParams.depthWrite = false;
  
  			} else {
  
  				materialParams.transparent = false;
  
  				if ( alphaMode === ALPHA_MODES.MASK ) {
  
  					materialParams.alphaTest = materialDef.alphaCutoff !== undefined ? materialDef.alphaCutoff : 0.5;
  
  				}
  
  			}
  
  			if ( materialDef.normalTexture !== undefined && materialType !== THREE.MeshBasicMaterial ) {
  
  				pending.push( parser.assignTexture( materialParams, 'normalMap', materialDef.normalTexture ) );
  				materialParams.normalScale = new THREE.Vector2( 1, 1 );
  
  				if ( materialDef.normalTexture.scale !== undefined ) {
  
  					const scale = materialDef.normalTexture.scale;
  					materialParams.normalScale.set( scale, scale );
  
  				}
  
  			}
  
  			if ( materialDef.occlusionTexture !== undefined && materialType !== THREE.MeshBasicMaterial ) {
  
  				pending.push( parser.assignTexture( materialParams, 'aoMap', materialDef.occlusionTexture ) );
  
  				if ( materialDef.occlusionTexture.strength !== undefined ) {
  
  					materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;
  
  				}
  
  			}
  
  			if ( materialDef.emissiveFactor !== undefined && materialType !== THREE.MeshBasicMaterial ) {
  
  				materialParams.emissive = new THREE.Color().fromArray( materialDef.emissiveFactor );
  
  			}
  
  			if ( materialDef.emissiveTexture !== undefined && materialType !== THREE.MeshBasicMaterial ) {
  
  				pending.push( parser.assignTexture( materialParams, 'emissiveMap', materialDef.emissiveTexture, THREE.sRGBEncoding ) );
  
  			}
  
  			return Promise.all( pending ).then( function () {
  
  				let material;
  
  				if ( materialType === GLTFMeshStandardSGMaterial ) {
  
  					material = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ].createMaterial( materialParams );
  
  				} else {
  
  					material = new materialType( materialParams );
  
  				}
  
  				if ( materialDef.name ) material.name = materialDef.name;
  				assignExtrasToUserData( material, materialDef );
  				parser.associations.set( material, {
  					materials: materialIndex
  				} );
  				if ( materialDef.extensions ) addUnknownExtensionsToUserData( extensions, material, materialDef );
  				return material;
  
  			} );
  
  		}
  		/** When THREE.Object3D instances are targeted by animation, they need unique names. */
  
  
  		createUniqueName( originalName ) {
  
  			const sanitizedName = THREE.PropertyBinding.sanitizeNodeName( originalName || '' );
  			let name = sanitizedName;
  
  			for ( let i = 1; this.nodeNamesUsed[ name ]; ++ i ) {
  
  				name = sanitizedName + '_' + i;
  
  			}
  
  			this.nodeNamesUsed[ name ] = true;
  			return name;
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#geometry
     *
     * Creates BufferGeometries from primitives.
     *
     * @param {Array<GLTF.Primitive>} primitives
     * @return {Promise<Array<BufferGeometry>>}
     */
  
  
  		loadGeometries( primitives ) {
  
  			const parser = this;
  			const extensions = this.extensions;
  			const cache = this.primitiveCache;
  
  			function createDracoPrimitive( primitive ) {
  
  				return extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ].decodePrimitive( primitive, parser ).then( function ( geometry ) {
  
  					return addPrimitiveAttributes( geometry, primitive, parser );
  
  				} );
  
  			}
  
  			const pending = [];
  
  			for ( let i = 0, il = primitives.length; i < il; i ++ ) {
  
  				const primitive = primitives[ i ];
  				const cacheKey = createPrimitiveKey( primitive ); // See if we've already created this geometry
  
  				const cached = cache[ cacheKey ];
  
  				if ( cached ) {
  
  					// Use the cached geometry if it exists
  					pending.push( cached.promise );
  
  				} else {
  
  					let geometryPromise;
  
  					if ( primitive.extensions && primitive.extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ] ) {
  
  						// Use DRACO geometry if available
  						geometryPromise = createDracoPrimitive( primitive );
  
  					} else {
  
  						// Otherwise create a new geometry
  						geometryPromise = addPrimitiveAttributes( new THREE.BufferGeometry(), primitive, parser );
  
  					} // Cache this geometry
  
  
  					cache[ cacheKey ] = {
  						primitive: primitive,
  						promise: geometryPromise
  					};
  					pending.push( geometryPromise );
  
  				}
  
  			}
  
  			return Promise.all( pending );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#meshes
     * @param {number} meshIndex
     * @return {Promise<Group|Mesh|SkinnedMesh>}
     */
  
  
  		loadMesh( meshIndex ) {
  
  			const parser = this;
  			const json = this.json;
  			const extensions = this.extensions;
  			const meshDef = json.meshes[ meshIndex ];
  			const primitives = meshDef.primitives;
  			const pending = [];
  
  			for ( let i = 0, il = primitives.length; i < il; i ++ ) {
  
  				const material = primitives[ i ].material === undefined ? createDefaultMaterial( this.cache ) : this.getDependency( 'material', primitives[ i ].material );
  				pending.push( material );
  
  			}
  
  			pending.push( parser.loadGeometries( primitives ) );
  			return Promise.all( pending ).then( function ( results ) {
  
  				const materials = results.slice( 0, results.length - 1 );
  				const geometries = results[ results.length - 1 ];
  				const meshes = [];
  
  				for ( let i = 0, il = geometries.length; i < il; i ++ ) {
  
  					const geometry = geometries[ i ];
  					const primitive = primitives[ i ]; // 1. create THREE.Mesh
  
  					let mesh;
  					const material = materials[ i ];
  
  					if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLES || primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP || primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN || primitive.mode === undefined ) {
  
  						// .isSkinnedMesh isn't in glTF spec. See ._markDefs()
  						mesh = meshDef.isSkinnedMesh === true ? new THREE.SkinnedMesh( geometry, material ) : new THREE.Mesh( geometry, material );
  
  						if ( mesh.isSkinnedMesh === true && ! mesh.geometry.attributes.skinWeight.normalized ) {
  
  							// we normalize floating point skin weight array to fix malformed assets (see #15319)
  							// it's important to skip this for non-float32 data since normalizeSkinWeights assumes non-normalized inputs
  							mesh.normalizeSkinWeights();
  
  						}
  
  						if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ) {
  
  							mesh.geometry = toTrianglesDrawMode( mesh.geometry, THREE.TriangleStripDrawMode );
  
  						} else if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ) {
  
  							mesh.geometry = toTrianglesDrawMode( mesh.geometry, THREE.TriangleFanDrawMode );
  
  						}
  
  					} else if ( primitive.mode === WEBGL_CONSTANTS.LINES ) {
  
  						mesh = new THREE.LineSegments( geometry, material );
  
  					} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_STRIP ) {
  
  						mesh = new THREE.Line( geometry, material );
  
  					} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_LOOP ) {
  
  						mesh = new THREE.LineLoop( geometry, material );
  
  					} else if ( primitive.mode === WEBGL_CONSTANTS.POINTS ) {
  
  						mesh = new THREE.Points( geometry, material );
  
  					} else {
  
  						throw new Error( 'THREE.GLTFLoader: Primitive mode unsupported: ' + primitive.mode );
  
  					}
  
  					if ( Object.keys( mesh.geometry.morphAttributes ).length > 0 ) {
  
  						updateMorphTargets( mesh, meshDef );
  
  					}
  
  					mesh.name = parser.createUniqueName( meshDef.name || 'mesh_' + meshIndex );
  					assignExtrasToUserData( mesh, meshDef );
  					if ( primitive.extensions ) addUnknownExtensionsToUserData( extensions, mesh, primitive );
  					parser.assignFinalMaterial( mesh );
  					meshes.push( mesh );
  
  				}
  
  				for ( let i = 0, il = meshes.length; i < il; i ++ ) {
  
  					parser.associations.set( meshes[ i ], {
  						meshes: meshIndex,
  						primitives: i
  					} );
  
  				}
  
  				if ( meshes.length === 1 ) {
  
  					return meshes[ 0 ];
  
  				}
  
  				const group = new THREE.Group();
  				parser.associations.set( group, {
  					meshes: meshIndex
  				} );
  
  				for ( let i = 0, il = meshes.length; i < il; i ++ ) {
  
  					group.add( meshes[ i ] );
  
  				}
  
  				return group;
  
  			} );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#cameras
     * @param {number} cameraIndex
     * @return {Promise<THREE.Camera>}
     */
  
  
  		loadCamera( cameraIndex ) {
  
  			let camera;
  			const cameraDef = this.json.cameras[ cameraIndex ];
  			const params = cameraDef[ cameraDef.type ];
  
  			if ( ! params ) {
  
  				console.warn( 'THREE.GLTFLoader: Missing camera parameters.' );
  				return;
  
  			}
  
  			if ( cameraDef.type === 'perspective' ) {
  
  				camera = new THREE.PerspectiveCamera( THREE.MathUtils.radToDeg( params.yfov ), params.aspectRatio || 1, params.znear || 1, params.zfar || 2e6 );
  
  			} else if ( cameraDef.type === 'orthographic' ) {
  
  				camera = new THREE.OrthographicCamera( - params.xmag, params.xmag, params.ymag, - params.ymag, params.znear, params.zfar );
  
  			}
  
  			if ( cameraDef.name ) camera.name = this.createUniqueName( cameraDef.name );
  			assignExtrasToUserData( camera, cameraDef );
  			return Promise.resolve( camera );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#skins
     * @param {number} skinIndex
     * @return {Promise<Object>}
     */
  
  
  		loadSkin( skinIndex ) {
  
  			const skinDef = this.json.skins[ skinIndex ];
  			const skinEntry = {
  				joints: skinDef.joints
  			};
  
  			if ( skinDef.inverseBindMatrices === undefined ) {
  
  				return Promise.resolve( skinEntry );
  
  			}
  
  			return this.getDependency( 'accessor', skinDef.inverseBindMatrices ).then( function ( accessor ) {
  
  				skinEntry.inverseBindMatrices = accessor;
  				return skinEntry;
  
  			} );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#animations
     * @param {number} animationIndex
     * @return {Promise<AnimationClip>}
     */
  
  
  		loadAnimation( animationIndex ) {
  
  			const json = this.json;
  			const animationDef = json.animations[ animationIndex ];
  			const pendingNodes = [];
  			const pendingInputAccessors = [];
  			const pendingOutputAccessors = [];
  			const pendingSamplers = [];
  			const pendingTargets = [];
  
  			for ( let i = 0, il = animationDef.channels.length; i < il; i ++ ) {
  
  				const channel = animationDef.channels[ i ];
  				const sampler = animationDef.samplers[ channel.sampler ];
  				const target = channel.target;
  				const name = target.node !== undefined ? target.node : target.id; // NOTE: target.id is deprecated.
  
  				const input = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.input ] : sampler.input;
  				const output = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.output ] : sampler.output;
  				pendingNodes.push( this.getDependency( 'node', name ) );
  				pendingInputAccessors.push( this.getDependency( 'accessor', input ) );
  				pendingOutputAccessors.push( this.getDependency( 'accessor', output ) );
  				pendingSamplers.push( sampler );
  				pendingTargets.push( target );
  
  			}
  
  			return Promise.all( [ Promise.all( pendingNodes ), Promise.all( pendingInputAccessors ), Promise.all( pendingOutputAccessors ), Promise.all( pendingSamplers ), Promise.all( pendingTargets ) ] ).then( function ( dependencies ) {
  
  				const nodes = dependencies[ 0 ];
  				const inputAccessors = dependencies[ 1 ];
  				const outputAccessors = dependencies[ 2 ];
  				const samplers = dependencies[ 3 ];
  				const targets = dependencies[ 4 ];
  				const tracks = [];
  
  				for ( let i = 0, il = nodes.length; i < il; i ++ ) {
  
  					const node = nodes[ i ];
  					const inputAccessor = inputAccessors[ i ];
  					const outputAccessor = outputAccessors[ i ];
  					const sampler = samplers[ i ];
  					const target = targets[ i ];
  					if ( node === undefined ) continue;
  					node.updateMatrix();
  					node.matrixAutoUpdate = true;
  					let TypedKeyframeTrack;
  
  					switch ( PATH_PROPERTIES[ target.path ] ) {
  
  						case PATH_PROPERTIES.weights:
  							TypedKeyframeTrack = THREE.NumberKeyframeTrack;
  							break;
  
  						case PATH_PROPERTIES.rotation:
  							TypedKeyframeTrack = THREE.QuaternionKeyframeTrack;
  							break;
  
  						case PATH_PROPERTIES.position:
  						case PATH_PROPERTIES.scale:
  						default:
  							TypedKeyframeTrack = THREE.VectorKeyframeTrack;
  							break;
  
  					}
  
  					const targetName = node.name ? node.name : node.uuid;
  					const interpolation = sampler.interpolation !== undefined ? INTERPOLATION[ sampler.interpolation ] : THREE.InterpolateLinear;
  					const targetNames = [];
  
  					if ( PATH_PROPERTIES[ target.path ] === PATH_PROPERTIES.weights ) {
  
  						node.traverse( function ( object ) {
  
  							if ( object.morphTargetInfluences ) {
  
  								targetNames.push( object.name ? object.name : object.uuid );
  
  							}
  
  						} );
  
  					} else {
  
  						targetNames.push( targetName );
  
  					}
  
  					let outputArray = outputAccessor.array;
  
  					if ( outputAccessor.normalized ) {
  
  						const scale = getNormalizedComponentScale( outputArray.constructor );
  						const scaled = new Float32Array( outputArray.length );
  
  						for ( let j = 0, jl = outputArray.length; j < jl; j ++ ) {
  
  							scaled[ j ] = outputArray[ j ] * scale;
  
  						}
  
  						outputArray = scaled;
  
  					}
  
  					for ( let j = 0, jl = targetNames.length; j < jl; j ++ ) {
  
  						const track = new TypedKeyframeTrack( targetNames[ j ] + '.' + PATH_PROPERTIES[ target.path ], inputAccessor.array, outputArray, interpolation ); // Override interpolation with custom factory method.
  
  						if ( sampler.interpolation === 'CUBICSPLINE' ) {
  
  							track.createInterpolant = function InterpolantFactoryMethodGLTFCubicSpline( result ) {
  
  								// A CUBICSPLINE keyframe in glTF has three output values for each input value,
  								// representing inTangent, splineVertex, and outTangent. As a result, track.getValueSize()
  								// must be divided by three to get the interpolant's sampleSize argument.
  								const interpolantType = this instanceof THREE.QuaternionKeyframeTrack ? GLTFCubicSplineQuaternionInterpolant : GLTFCubicSplineInterpolant;
  								return new interpolantType( this.times, this.values, this.getValueSize() / 3, result );
  
  							}; // Mark as CUBICSPLINE. `track.getInterpolation()` doesn't support custom interpolants.
  
  
  							track.createInterpolant.isInterpolantFactoryMethodGLTFCubicSpline = true;
  
  						}
  
  						tracks.push( track );
  
  					}
  
  				}
  
  				const name = animationDef.name ? animationDef.name : 'animation_' + animationIndex;
  				return new THREE.AnimationClip( name, undefined, tracks );
  
  			} );
  
  		}
  
  		createNodeMesh( nodeIndex ) {
  
  			const json = this.json;
  			const parser = this;
  			const nodeDef = json.nodes[ nodeIndex ];
  			if ( nodeDef.mesh === undefined ) return null;
  			return parser.getDependency( 'mesh', nodeDef.mesh ).then( function ( mesh ) {
  
  				const node = parser._getNodeRef( parser.meshCache, nodeDef.mesh, mesh ); // if weights are provided on the node, override weights on the mesh.
  
  
  				if ( nodeDef.weights !== undefined ) {
  
  					node.traverse( function ( o ) {
  
  						if ( ! o.isMesh ) return;
  
  						for ( let i = 0, il = nodeDef.weights.length; i < il; i ++ ) {
  
  							o.morphTargetInfluences[ i ] = nodeDef.weights[ i ];
  
  						}
  
  					} );
  
  				}
  
  				return node;
  
  			} );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#nodes-and-hierarchy
     * @param {number} nodeIndex
     * @return {Promise<Object3D>}
     */
  
  
  		loadNode( nodeIndex ) {
  
  			const json = this.json;
  			const extensions = this.extensions;
  			const parser = this;
  			const nodeDef = json.nodes[ nodeIndex ]; // reserve node's name before its dependencies, so the root has the intended name.
  
  			const nodeName = nodeDef.name ? parser.createUniqueName( nodeDef.name ) : '';
  			return function () {
  
  				const pending = [];
  
  				const meshPromise = parser._invokeOne( function ( ext ) {
  
  					return ext.createNodeMesh && ext.createNodeMesh( nodeIndex );
  
  				} );
  
  				if ( meshPromise ) {
  
  					pending.push( meshPromise );
  
  				}
  
  				if ( nodeDef.camera !== undefined ) {
  
  					pending.push( parser.getDependency( 'camera', nodeDef.camera ).then( function ( camera ) {
  
  						return parser._getNodeRef( parser.cameraCache, nodeDef.camera, camera );
  
  					} ) );
  
  				}
  
  				parser._invokeAll( function ( ext ) {
  
  					return ext.createNodeAttachment && ext.createNodeAttachment( nodeIndex );
  
  				} ).forEach( function ( promise ) {
  
  					pending.push( promise );
  
  				} );
  
  				return Promise.all( pending );
  
  			}().then( function ( objects ) {
  
  				let node; // .isBone isn't in glTF spec. See ._markDefs
  
  				if ( nodeDef.isBone === true ) {
  
  					node = new THREE.Bone();
  
  				} else if ( objects.length > 1 ) {
  
  					node = new THREE.Group();
  
  				} else if ( objects.length === 1 ) {
  
  					node = objects[ 0 ];
  
  				} else {
  
  					node = new THREE.Object3D();
  
  				}
  
  				if ( node !== objects[ 0 ] ) {
  
  					for ( let i = 0, il = objects.length; i < il; i ++ ) {
  
  						node.add( objects[ i ] );
  
  					}
  
  				}
  
  				if ( nodeDef.name ) {
  
  					node.userData.name = nodeDef.name;
  					node.name = nodeName;
  
  				}
  
  				assignExtrasToUserData( node, nodeDef );
  				if ( nodeDef.extensions ) addUnknownExtensionsToUserData( extensions, node, nodeDef );
  
  				if ( nodeDef.matrix !== undefined ) {
  
  					const matrix = new THREE.Matrix4();
  					matrix.fromArray( nodeDef.matrix );
  					node.applyMatrix4( matrix );
  
  				} else {
  
  					if ( nodeDef.translation !== undefined ) {
  
  						node.position.fromArray( nodeDef.translation );
  
  					}
  
  					if ( nodeDef.rotation !== undefined ) {
  
  						node.quaternion.fromArray( nodeDef.rotation );
  
  					}
  
  					if ( nodeDef.scale !== undefined ) {
  
  						node.scale.fromArray( nodeDef.scale );
  
  					}
  
  				}
  
  				if ( ! parser.associations.has( node ) ) {
  
  					parser.associations.set( node, {} );
  
  				}
  
  				parser.associations.get( node ).nodes = nodeIndex;
  				return node;
  
  			} );
  
  		}
  		/**
     * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#scenes
     * @param {number} sceneIndex
     * @return {Promise<Group>}
     */
  
  
  		loadScene( sceneIndex ) {
  
  			const json = this.json;
  			const extensions = this.extensions;
  			const sceneDef = this.json.scenes[ sceneIndex ];
  			const parser = this; // THREE.Loader returns THREE.Group, not Scene.
  			// See: https://github.com/mrdoob/three.js/issues/18342#issuecomment-578981172
  
  			const scene = new THREE.Group();
  			if ( sceneDef.name ) scene.name = parser.createUniqueName( sceneDef.name );
  			assignExtrasToUserData( scene, sceneDef );
  			if ( sceneDef.extensions ) addUnknownExtensionsToUserData( extensions, scene, sceneDef );
  			const nodeIds = sceneDef.nodes || [];
  			const pending = [];
  
  			for ( let i = 0, il = nodeIds.length; i < il; i ++ ) {
  
  				pending.push( buildNodeHierarchy( nodeIds[ i ], scene, json, parser ) );
  
  			}
  
  			return Promise.all( pending ).then( function () {
  
  				// Removes dangling associations, associations that reference a node that
  				// didn't make it into the scene.
  				const reduceAssociations = node => {
  
  					const reducedAssociations = new Map();
  
  					for ( const [ key, value ] of parser.associations ) {
  
  						if ( key instanceof THREE.Material || key instanceof THREE.Texture ) {
  
  							reducedAssociations.set( key, value );
  
  						}
  
  					}
  
  					node.traverse( node => {
  
  						const mappings = parser.associations.get( node );
  
  						if ( mappings != null ) {
  
  							reducedAssociations.set( node, mappings );
  
  						}
  
  					} );
  					return reducedAssociations;
  
  				};
  
  				parser.associations = reduceAssociations( scene );
  				return scene;
  
  			} );
  
  		}
  
  	}
  
  	function buildNodeHierarchy( nodeId, parentObject, json, parser ) {
  
  		const nodeDef = json.nodes[ nodeId ];
  		return parser.getDependency( 'node', nodeId ).then( function ( node ) {
  
  			if ( nodeDef.skin === undefined ) return node; // build skeleton here as well
  
  			let skinEntry;
  			return parser.getDependency( 'skin', nodeDef.skin ).then( function ( skin ) {
  
  				skinEntry = skin;
  				const pendingJoints = [];
  
  				for ( let i = 0, il = skinEntry.joints.length; i < il; i ++ ) {
  
  					pendingJoints.push( parser.getDependency( 'node', skinEntry.joints[ i ] ) );
  
  				}
  
  				return Promise.all( pendingJoints );
  
  			} ).then( function ( jointNodes ) {
  
  				node.traverse( function ( mesh ) {
  
  					if ( ! mesh.isMesh ) return;
  					const bones = [];
  					const boneInverses = [];
  
  					for ( let j = 0, jl = jointNodes.length; j < jl; j ++ ) {
  
  						const jointNode = jointNodes[ j ];
  
  						if ( jointNode ) {
  
  							bones.push( jointNode );
  							const mat = new THREE.Matrix4();
  
  							if ( skinEntry.inverseBindMatrices !== undefined ) {
  
  								mat.fromArray( skinEntry.inverseBindMatrices.array, j * 16 );
  
  							}
  
  							boneInverses.push( mat );
  
  						} else {
  
  							console.warn( 'THREE.GLTFLoader: Joint "%s" could not be found.', skinEntry.joints[ j ] );
  
  						}
  
  					}
  
  					mesh.bind( new THREE.Skeleton( bones, boneInverses ), mesh.matrixWorld );
  
  				} );
  				return node;
  
  			} );
  
  		} ).then( function ( node ) {
  
  			// build node hierachy
  			parentObject.add( node );
  			const pending = [];
  
  			if ( nodeDef.children ) {
  
  				const children = nodeDef.children;
  
  				for ( let i = 0, il = children.length; i < il; i ++ ) {
  
  					const child = children[ i ];
  					pending.push( buildNodeHierarchy( child, node, json, parser ) );
  
  				}
  
  			}
  
  			return Promise.all( pending );
  
  		} );
  
  	}
  	/**
   * @param {BufferGeometry} geometry
   * @param {GLTF.Primitive} primitiveDef
   * @param {GLTFParser} parser
   */
  
  
  	function computeBounds( geometry, primitiveDef, parser ) {
  
  		const attributes = primitiveDef.attributes;
  		const box = new THREE.Box3();
  
  		if ( attributes.POSITION !== undefined ) {
  
  			const accessor = parser.json.accessors[ attributes.POSITION ];
  			const min = accessor.min;
  			const max = accessor.max; // glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.
  
  			if ( min !== undefined && max !== undefined ) {
  
  				box.set( new THREE.Vector3( min[ 0 ], min[ 1 ], min[ 2 ] ), new THREE.Vector3( max[ 0 ], max[ 1 ], max[ 2 ] ) );
  
  				if ( accessor.normalized ) {
  
  					const boxScale = getNormalizedComponentScale( WEBGL_COMPONENT_TYPES[ accessor.componentType ] );
  					box.min.multiplyScalar( boxScale );
  					box.max.multiplyScalar( boxScale );
  
  				}
  
  			} else {
  
  				console.warn( 'THREE.GLTFLoader: Missing min/max properties for accessor POSITION.' );
  				return;
  
  			}
  
  		} else {
  
  			return;
  
  		}
  
  		const targets = primitiveDef.targets;
  
  		if ( targets !== undefined ) {
  
  			const maxDisplacement = new THREE.Vector3();
  			const vector = new THREE.Vector3();
  
  			for ( let i = 0, il = targets.length; i < il; i ++ ) {
  
  				const target = targets[ i ];
  
  				if ( target.POSITION !== undefined ) {
  
  					const accessor = parser.json.accessors[ target.POSITION ];
  					const min = accessor.min;
  					const max = accessor.max; // glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.
  
  					if ( min !== undefined && max !== undefined ) {
  
  						// we need to get max of absolute components because target weight is [-1,1]
  						vector.setX( Math.max( Math.abs( min[ 0 ] ), Math.abs( max[ 0 ] ) ) );
  						vector.setY( Math.max( Math.abs( min[ 1 ] ), Math.abs( max[ 1 ] ) ) );
  						vector.setZ( Math.max( Math.abs( min[ 2 ] ), Math.abs( max[ 2 ] ) ) );
  
  						if ( accessor.normalized ) {
  
  							const boxScale = getNormalizedComponentScale( WEBGL_COMPONENT_TYPES[ accessor.componentType ] );
  							vector.multiplyScalar( boxScale );
  
  						} // Note: this assumes that the sum of all weights is at most 1. This isn't quite correct - it's more conservative
  						// to assume that each target can have a max weight of 1. However, for some use cases - notably, when morph targets
  						// are used to implement key-frame animations and as such only two are active at a time - this results in very large
  						// boxes. So for now we make a box that's sometimes a touch too small but is hopefully mostly of reasonable size.
  
  
  						maxDisplacement.max( vector );
  
  					} else {
  
  						console.warn( 'THREE.GLTFLoader: Missing min/max properties for accessor POSITION.' );
  
  					}
  
  				}
  
  			} // As per comment above this box isn't conservative, but has a reasonable size for a very large number of morph targets.
  
  
  			box.expandByVector( maxDisplacement );
  
  		}
  
  		geometry.boundingBox = box;
  		const sphere = new THREE.Sphere();
  		box.getCenter( sphere.center );
  		sphere.radius = box.min.distanceTo( box.max ) / 2;
  		geometry.boundingSphere = sphere;
  
  	}
  	/**
   * @param {BufferGeometry} geometry
   * @param {GLTF.Primitive} primitiveDef
   * @param {GLTFParser} parser
   * @return {Promise<BufferGeometry>}
   */
  
  
  	function addPrimitiveAttributes( geometry, primitiveDef, parser ) {
  
  		const attributes = primitiveDef.attributes;
  		const pending = [];
  
  		function assignAttributeAccessor( accessorIndex, attributeName ) {
  
  			return parser.getDependency( 'accessor', accessorIndex ).then( function ( accessor ) {
  
  				geometry.setAttribute( attributeName, accessor );
  
  			} );
  
  		}
  
  		for ( const gltfAttributeName in attributes ) {
  
  			const threeAttributeName = ATTRIBUTES[ gltfAttributeName ] || gltfAttributeName.toLowerCase(); // Skip attributes already provided by e.g. Draco extension.
  
  			if ( threeAttributeName in geometry.attributes ) continue;
  			pending.push( assignAttributeAccessor( attributes[ gltfAttributeName ], threeAttributeName ) );
  
  		}
  
  		if ( primitiveDef.indices !== undefined && ! geometry.index ) {
  
  			const accessor = parser.getDependency( 'accessor', primitiveDef.indices ).then( function ( accessor ) {
  
  				geometry.setIndex( accessor );
  
  			} );
  			pending.push( accessor );
  
  		}
  
  		assignExtrasToUserData( geometry, primitiveDef );
  		computeBounds( geometry, primitiveDef, parser );
  		return Promise.all( pending ).then( function () {
  
  			return primitiveDef.targets !== undefined ? addMorphTargets( geometry, primitiveDef.targets, parser ) : geometry;
  
  		} );
  
  	}
  	/**
   * @param {BufferGeometry} geometry
   * @param {Number} drawMode
   * @return {BufferGeometry}
   */
  
  
  	function toTrianglesDrawMode( geometry, drawMode ) {
  
  		let index = geometry.getIndex(); // generate index if not present
  
  		if ( index === null ) {
  
  			const indices = [];
  			const position = geometry.getAttribute( 'position' );
  
  			if ( position !== undefined ) {
  
  				for ( let i = 0; i < position.count; i ++ ) {
  
  					indices.push( i );
  
  				}
  
  				geometry.setIndex( indices );
  				index = geometry.getIndex();
  
  			} else {
  
  				console.error( 'THREE.GLTFLoader.toTrianglesDrawMode(): Undefined position attribute. Processing not possible.' );
  				return geometry;
  
  			}
  
  		} //
  
  
  		const numberOfTriangles = index.count - 2;
  		const newIndices = [];
  
  		if ( drawMode === THREE.TriangleFanDrawMode ) {
  
  			// gl.TRIANGLE_FAN
  			for ( let i = 1; i <= numberOfTriangles; i ++ ) {
  
  				newIndices.push( index.getX( 0 ) );
  				newIndices.push( index.getX( i ) );
  				newIndices.push( index.getX( i + 1 ) );
  
  			}
  
  		} else {
  
  			// gl.TRIANGLE_STRIP
  			for ( let i = 0; i < numberOfTriangles; i ++ ) {
  
  				if ( i % 2 === 0 ) {
  
  					newIndices.push( index.getX( i ) );
  					newIndices.push( index.getX( i + 1 ) );
  					newIndices.push( index.getX( i + 2 ) );
  
  				} else {
  
  					newIndices.push( index.getX( i + 2 ) );
  					newIndices.push( index.getX( i + 1 ) );
  					newIndices.push( index.getX( i ) );
  
  				}
  
  			}
  
  		}
  
  		if ( newIndices.length / 3 !== numberOfTriangles ) {
  
  			console.error( 'THREE.GLTFLoader.toTrianglesDrawMode(): Unable to generate correct amount of triangles.' );
  
  		} // build final geometry
  
  
  		const newGeometry = geometry.clone();
  		newGeometry.setIndex( newIndices );
  		return newGeometry;
  
  	}
  
  	THREE.GLTFLoader = GLTFLoader;
  
  } )();
  